This document analyzes the spatiotemporal patterns of H5N1 avian influenza outbreaks globally between 2003 and 2006. It identifies three phases of the H5N1 epidemic and uses space-time cluster analysis to detect six disease cluster patterns along major bird migration flyways. The matching of outbreak clusters with wild bird migration patterns suggests wild birds may play an important role in long-distance spread of H5N1. Short-distance spread is also potentially linked to wild birds spreading the virus at sites where they overwinter or migrate through.
Dossier transmission: Transmission of Avian Influenza Virus to DogsHarm Kiezebrink
Avian influenza was found in a dog on a farm in South Gyeongsang Province amid growing concerns that the disease could spread to other animals, officials the Ministry of Agriculture, Food and Rural Affairs said. The dog ― one of three at a duck farm in Goseong-gun, South Gyeongsang Province ― had antigens for the highly pathogenic H5N8 strain of bird flu, the Ministry of Agriculture, Food and Rural Affairs said. The disease affected the farm on Jan. 23.
Since the first case of a dog being infected with the poultry virus in March 2014, there have been 55 dogs found with antibodies to the bird flu virus. The antibody means the immune system of the dogs eliminated the virus. This is the first time bird flu has been found in a dog in Korea through the detection of antigens.
“None of these dogs had shown symptoms. No antigens or antibodies for the virus were found in the two other dogs, which means that dog-to-dog transmission is unlikely to have happened,” quarantine officials said.
The ministry suspected that the dog may have eaten infected animals at the farm. All poultry and dogs at the concerned farm were slaughtered as part of the preventive measures right after the farm was reported to have been infected with the disease, officials said.
Meanwhile, quarantine officials rejected the possibility of viral transmission to humans. According to the ministry’s report, about 450 workers at infected farms across the country had been given an antigen test, with none showing signs of infection. None of Korea’s 20,000 farm workers have reported any symptoms so far, officials added.
“It is thought that infected dogs do not show symptoms of the disease as they are naturally resistant to bird flu,” the ministry said. Meanwhile, the Agriculture Ministry has toughened the quarantine measures in Goseong-gun. The region is a frequented by migratory birds, which are suspected to have spread the viral disease.
H5N8 virus dutch outbreak (2014) linked to sequences of strains from asiaHarm Kiezebrink
Genetic analysis of influenza A(H5N8) virus from the Netherlands indicates that the virus probably was spread by migratory wild birds from Asia, possibly through overlapping flyways and common breeding sites in Siberia. In addition to the outbreak in the Netherlands, several other outbreaks of HPAI (H5N8) virus infections were reported in Europe at the end of 2014 after exponentially increasing deaths occurred in chicken and turkey flocks.
Genetic sequences submitted to the EpiFlu database indicated that the viruses from Europe showed a strong similarity to viruses isolated earlier in 2014 in South Korea, China, and Japan. An H5N8 virus isolated from a wigeon in Russia in September 2014 is located in the phylogenetic tree near the node of all sequences for H5N8 viruses from Europe.
In regard to time, this location fits the hypothesized route of H5N8 virus introduction into Europe. Furthermore, for several reasons, it is highly likely that the introduction of HPAI (H5N8) virus into the indoor-layer farm in the Netherlands occurred via indirect contact.
First, despite intensive monitoring, H5N8 viruses have never been detected in commercial poultry or wild birds in the Netherlands.
Second, when the virus was detected, the Netherlands had no direct trade contact with other European countries or Asia that might explain a route of introduction.
Third, because of the severity of disease in galliforms, outbreaks of H5N8 in the Netherlands before November 2014 would have been noticed.
The 3 P’s of avian influenza Prevent, Plan, PracticeHarm Kiezebrink
Avian Influenza has become endemic in many parts of the word. In it's current form it has been around since 1997 and although thy virus types have changed, emergency response, management & control are still a hot issue. In this article published in 2006 in the US magazine Poultry Perspectives, the subject what to do during crisis situations is presented. The conclusions are still valid today and may help to prevent large-scale outbreaks
Outbreak of High Patogen Avian Influenza H5N8 in GermanyHarm Kiezebrink
Germany has reported an outbreak of highly pathogenic avian influenza, H5N8 in fattening turkeys in North East Germany
(Mecklenburg - Western Pomerania). Increased mortality was observed in one of the six sheds of 15 week old birds for fattening (total number of turkeys on the premises ~ 31,000 of which each shed contained 5,000).
Human-to-Human transmission of H7H7 in Holland 2003Harm Kiezebrink
The outbreak of highly pathogenic avian influenza A virus subtype H7N7 started at the end of February, 2003, in commercial poultry farms in the Netherlands. In this study, published in The Lancet in 2004, it is noted that an unexpectedly high number of transmissions of avian influenza A virus subtype H7N7 to people directly involved in handling infected poultry, providing evidence for person-to-person transmission.
Although the risk of transmission of these viruses to humans was initially thought to be low, an outbreak investigation was launched to assess the extent of transmission of influenza A virus subtype H7N7 from chickens to humans.
453 people had health complaints—349 reported conjunctivitis, 90 had influenza-like illness, and 67 had other complaints. We detected A/H7 in conjunctival samples from 78 (26·4%) people with conjunctivitis only, in five (9·4%) with influenza-like illness and conjunctivitis, in two (5·4%) with influenza-like illness only, and in four (6%) who reported other symptoms. Most positive samples had been collected within 5 days of symptom onset. A/H7 infection was confirmed in three contacts (of 83 tested), one of whom developed influenza-like illness. Six people had influenza A/H3N2 infection. After 19 people had been diagnosed with the infection, all workers received mandatory influenza virus vaccination and prophylactic treatment with oseltamivir. More than half (56%) of A/H7 infections reported here arose before the vaccination and treatment programme.
Avian influenza virus-infected poultry can release a large amount of virus-contaminated droppings that serve as sources of infection for susceptible birds. Much research so far has focused on virus spread within flocks. However, as fecal material or manure is a major constituent of airborne poultry dust, virus-contaminated particulate matter from infected flocks may be dispersed into the environment.
This study, demonstrates the presence of airborne influenza virus RNA downwind from buildings holding LPAI-infected birds, and the observed correlation between field data on airborne poultry and livestock associated microbial exposure and the OPS-ST model. These findings suggest that geographical estimates of areas at high risk for human and animal exposure to airborne influenza virus can be modeled during an outbreak, although additional field measurements are needed to validate this proposition. In addition, the outdoor detection of influenza virus contaminated airborne dust during outbreaks in poultry suggests that practical measures can assist in the control of future influenza outbreaks.
In general, exposure to airborne influenza virus on commercial poultry farms could be reduced both by minimizing the initial generation of airborne particles and implementing methods for abatement of particles once generated. As an example, emergency mass culling of poultry using a foam blanket over the birds instead of labor-intensive whole-house gassing followed by ventilation reduces both exposure of cullers and dispersion of contaminated dust into the environment, contributing to the control of influenza outbreaks.
Reseach on H9N2: evidence that link outbreaks in Eurasia, China, South Korea,...Harm Kiezebrink
In this study, scientists from the U.S. Geological Survey and U.S. Fish and Wildlife Service harnessed a new type of DNA technology to investigate avian influenza viruses in Alaska. Using a “next generation” sequencing approach, which identifies gene sequences of interest more rapidly and more completely than by traditional techniques, scientists identified low pathogenic avian influenza viruses in Alaska that are nearly identical to viruses found in China and South Korea.
The viruses were found in an area of western Alaska that is known to be a hot spot for both American and Eurasian forms of avian influenza.
“Our past research in western Alaska has shown that 70 percent of avian influenza viruses isolated in this area were found to contain genetic material from Eurasia, providing evidence for high levels of intercontinental viral exchange,” said Andy Ramey, a scientist with the USGS Alaska Science Center and lead author of the study. “This is because Asian and North American migratory flyways overlap in western Alaska.”
The new study, led by the USGS, found low pathogenic H9N2 viruses in an Emperor Goose and a Northern Pintail. Both of the H9N2 viruses were nearly identical genetically to viruses found in wild bird samples from Lake Dongting, China and Cheon-su Bay, South Korea.
“These H9N2 viruses are low pathogenic and not known to infect humans, but similar viruses have been implicated in disease outbreaks in domestic poultry in Asia,” said Ramey.
There is no commercial poultry production in western Alaska and highly similar H9N2 virus strains have not been reported in poultry in East Asia or North America, so it is unlikely that agricultural imports influenced this result.
The finding provides evidence for intercontinental movement of intact avian influenza viruses by migratory birds. The USGS recently released a publication about the detection of a novel highly pathogenic H5N8 virus in the U.S. that is highly similar to the Eurasian H5N8 viruses. This suggests that the novel re-assortment may be adapted to certain waterfowl species, enabling it to survive long migrations. That virus, and associated strains, have now spread from early detections in wild and domestic birds in Pacific states to poultry outbreaks in Minnesota, Missouri and Arkansas.
“The frequency of inter-hemispheric dispersal events of avian influenza viruses by migratory birds may be higher than previously recognized,” said Ramey.
While some of the samples for the project came from bird fecal samples collected from beaches at Izembek National Wildlife Refuge, most of the samples came from sport hunters.
“For the past several years, we’ve worked closely with sport hunters in the fall to obtain swab samples from birds and that has really informed our understanding of wildlife disease in this area,” said Bruce Casler, formerly a biologist with the USFWS Izembek National Wildlife Refuge and a co-author of the study. Non
Spatial, temporal and genetic dynamics of H5N1 in chinaHarm Kiezebrink
The spatial spread of H5N1 avian influenza, significant ongoing mutations, and long-term persistence of the virus in some geographic regions has had an enormous impact on the poultry industry and presents a serious threat to human health.
This study revealed two different transmission modes of H5N1 viruses in China, and indicated a significant role of poultry in virus dissemination. Furthermore, selective pressure posed by vaccination was found in virus evolution in the country.
Phylogenetic analysis, geospatial techniques, and time series models were applied to investigate the spatiotemporal pattern of H5N1 outbreaks in China and the effect of vaccination on virus evolution.
Results showed obvious spatial and temporal clusters of H5N1 outbreaks on different scales, which may have been associated with poultry and wild-bird transmission modes of H5N1 viruses. Lead–lag relationships were found among poultry and wild-bird outbreaks and human cases. Human cases were preceded by poultry outbreaks, and wild-bird outbreaks were led by human cases.
Each clade has gained its own unique spatiotemporal and genetic dominance. Genetic diversity of the H5N1 virus decreased significantly between 1996 and 2011; presumably under strong selective pressure of vaccination. Mean evolutionary rates of H5N1 virus increased after vaccination was adopted in China.
Dossier transmission: Transmission of Avian Influenza Virus to DogsHarm Kiezebrink
Avian influenza was found in a dog on a farm in South Gyeongsang Province amid growing concerns that the disease could spread to other animals, officials the Ministry of Agriculture, Food and Rural Affairs said. The dog ― one of three at a duck farm in Goseong-gun, South Gyeongsang Province ― had antigens for the highly pathogenic H5N8 strain of bird flu, the Ministry of Agriculture, Food and Rural Affairs said. The disease affected the farm on Jan. 23.
Since the first case of a dog being infected with the poultry virus in March 2014, there have been 55 dogs found with antibodies to the bird flu virus. The antibody means the immune system of the dogs eliminated the virus. This is the first time bird flu has been found in a dog in Korea through the detection of antigens.
“None of these dogs had shown symptoms. No antigens or antibodies for the virus were found in the two other dogs, which means that dog-to-dog transmission is unlikely to have happened,” quarantine officials said.
The ministry suspected that the dog may have eaten infected animals at the farm. All poultry and dogs at the concerned farm were slaughtered as part of the preventive measures right after the farm was reported to have been infected with the disease, officials said.
Meanwhile, quarantine officials rejected the possibility of viral transmission to humans. According to the ministry’s report, about 450 workers at infected farms across the country had been given an antigen test, with none showing signs of infection. None of Korea’s 20,000 farm workers have reported any symptoms so far, officials added.
“It is thought that infected dogs do not show symptoms of the disease as they are naturally resistant to bird flu,” the ministry said. Meanwhile, the Agriculture Ministry has toughened the quarantine measures in Goseong-gun. The region is a frequented by migratory birds, which are suspected to have spread the viral disease.
H5N8 virus dutch outbreak (2014) linked to sequences of strains from asiaHarm Kiezebrink
Genetic analysis of influenza A(H5N8) virus from the Netherlands indicates that the virus probably was spread by migratory wild birds from Asia, possibly through overlapping flyways and common breeding sites in Siberia. In addition to the outbreak in the Netherlands, several other outbreaks of HPAI (H5N8) virus infections were reported in Europe at the end of 2014 after exponentially increasing deaths occurred in chicken and turkey flocks.
Genetic sequences submitted to the EpiFlu database indicated that the viruses from Europe showed a strong similarity to viruses isolated earlier in 2014 in South Korea, China, and Japan. An H5N8 virus isolated from a wigeon in Russia in September 2014 is located in the phylogenetic tree near the node of all sequences for H5N8 viruses from Europe.
In regard to time, this location fits the hypothesized route of H5N8 virus introduction into Europe. Furthermore, for several reasons, it is highly likely that the introduction of HPAI (H5N8) virus into the indoor-layer farm in the Netherlands occurred via indirect contact.
First, despite intensive monitoring, H5N8 viruses have never been detected in commercial poultry or wild birds in the Netherlands.
Second, when the virus was detected, the Netherlands had no direct trade contact with other European countries or Asia that might explain a route of introduction.
Third, because of the severity of disease in galliforms, outbreaks of H5N8 in the Netherlands before November 2014 would have been noticed.
The 3 P’s of avian influenza Prevent, Plan, PracticeHarm Kiezebrink
Avian Influenza has become endemic in many parts of the word. In it's current form it has been around since 1997 and although thy virus types have changed, emergency response, management & control are still a hot issue. In this article published in 2006 in the US magazine Poultry Perspectives, the subject what to do during crisis situations is presented. The conclusions are still valid today and may help to prevent large-scale outbreaks
Outbreak of High Patogen Avian Influenza H5N8 in GermanyHarm Kiezebrink
Germany has reported an outbreak of highly pathogenic avian influenza, H5N8 in fattening turkeys in North East Germany
(Mecklenburg - Western Pomerania). Increased mortality was observed in one of the six sheds of 15 week old birds for fattening (total number of turkeys on the premises ~ 31,000 of which each shed contained 5,000).
Human-to-Human transmission of H7H7 in Holland 2003Harm Kiezebrink
The outbreak of highly pathogenic avian influenza A virus subtype H7N7 started at the end of February, 2003, in commercial poultry farms in the Netherlands. In this study, published in The Lancet in 2004, it is noted that an unexpectedly high number of transmissions of avian influenza A virus subtype H7N7 to people directly involved in handling infected poultry, providing evidence for person-to-person transmission.
Although the risk of transmission of these viruses to humans was initially thought to be low, an outbreak investigation was launched to assess the extent of transmission of influenza A virus subtype H7N7 from chickens to humans.
453 people had health complaints—349 reported conjunctivitis, 90 had influenza-like illness, and 67 had other complaints. We detected A/H7 in conjunctival samples from 78 (26·4%) people with conjunctivitis only, in five (9·4%) with influenza-like illness and conjunctivitis, in two (5·4%) with influenza-like illness only, and in four (6%) who reported other symptoms. Most positive samples had been collected within 5 days of symptom onset. A/H7 infection was confirmed in three contacts (of 83 tested), one of whom developed influenza-like illness. Six people had influenza A/H3N2 infection. After 19 people had been diagnosed with the infection, all workers received mandatory influenza virus vaccination and prophylactic treatment with oseltamivir. More than half (56%) of A/H7 infections reported here arose before the vaccination and treatment programme.
Avian influenza virus-infected poultry can release a large amount of virus-contaminated droppings that serve as sources of infection for susceptible birds. Much research so far has focused on virus spread within flocks. However, as fecal material or manure is a major constituent of airborne poultry dust, virus-contaminated particulate matter from infected flocks may be dispersed into the environment.
This study, demonstrates the presence of airborne influenza virus RNA downwind from buildings holding LPAI-infected birds, and the observed correlation between field data on airborne poultry and livestock associated microbial exposure and the OPS-ST model. These findings suggest that geographical estimates of areas at high risk for human and animal exposure to airborne influenza virus can be modeled during an outbreak, although additional field measurements are needed to validate this proposition. In addition, the outdoor detection of influenza virus contaminated airborne dust during outbreaks in poultry suggests that practical measures can assist in the control of future influenza outbreaks.
In general, exposure to airborne influenza virus on commercial poultry farms could be reduced both by minimizing the initial generation of airborne particles and implementing methods for abatement of particles once generated. As an example, emergency mass culling of poultry using a foam blanket over the birds instead of labor-intensive whole-house gassing followed by ventilation reduces both exposure of cullers and dispersion of contaminated dust into the environment, contributing to the control of influenza outbreaks.
Reseach on H9N2: evidence that link outbreaks in Eurasia, China, South Korea,...Harm Kiezebrink
In this study, scientists from the U.S. Geological Survey and U.S. Fish and Wildlife Service harnessed a new type of DNA technology to investigate avian influenza viruses in Alaska. Using a “next generation” sequencing approach, which identifies gene sequences of interest more rapidly and more completely than by traditional techniques, scientists identified low pathogenic avian influenza viruses in Alaska that are nearly identical to viruses found in China and South Korea.
The viruses were found in an area of western Alaska that is known to be a hot spot for both American and Eurasian forms of avian influenza.
“Our past research in western Alaska has shown that 70 percent of avian influenza viruses isolated in this area were found to contain genetic material from Eurasia, providing evidence for high levels of intercontinental viral exchange,” said Andy Ramey, a scientist with the USGS Alaska Science Center and lead author of the study. “This is because Asian and North American migratory flyways overlap in western Alaska.”
The new study, led by the USGS, found low pathogenic H9N2 viruses in an Emperor Goose and a Northern Pintail. Both of the H9N2 viruses were nearly identical genetically to viruses found in wild bird samples from Lake Dongting, China and Cheon-su Bay, South Korea.
“These H9N2 viruses are low pathogenic and not known to infect humans, but similar viruses have been implicated in disease outbreaks in domestic poultry in Asia,” said Ramey.
There is no commercial poultry production in western Alaska and highly similar H9N2 virus strains have not been reported in poultry in East Asia or North America, so it is unlikely that agricultural imports influenced this result.
The finding provides evidence for intercontinental movement of intact avian influenza viruses by migratory birds. The USGS recently released a publication about the detection of a novel highly pathogenic H5N8 virus in the U.S. that is highly similar to the Eurasian H5N8 viruses. This suggests that the novel re-assortment may be adapted to certain waterfowl species, enabling it to survive long migrations. That virus, and associated strains, have now spread from early detections in wild and domestic birds in Pacific states to poultry outbreaks in Minnesota, Missouri and Arkansas.
“The frequency of inter-hemispheric dispersal events of avian influenza viruses by migratory birds may be higher than previously recognized,” said Ramey.
While some of the samples for the project came from bird fecal samples collected from beaches at Izembek National Wildlife Refuge, most of the samples came from sport hunters.
“For the past several years, we’ve worked closely with sport hunters in the fall to obtain swab samples from birds and that has really informed our understanding of wildlife disease in this area,” said Bruce Casler, formerly a biologist with the USFWS Izembek National Wildlife Refuge and a co-author of the study. Non
Spatial, temporal and genetic dynamics of H5N1 in chinaHarm Kiezebrink
The spatial spread of H5N1 avian influenza, significant ongoing mutations, and long-term persistence of the virus in some geographic regions has had an enormous impact on the poultry industry and presents a serious threat to human health.
This study revealed two different transmission modes of H5N1 viruses in China, and indicated a significant role of poultry in virus dissemination. Furthermore, selective pressure posed by vaccination was found in virus evolution in the country.
Phylogenetic analysis, geospatial techniques, and time series models were applied to investigate the spatiotemporal pattern of H5N1 outbreaks in China and the effect of vaccination on virus evolution.
Results showed obvious spatial and temporal clusters of H5N1 outbreaks on different scales, which may have been associated with poultry and wild-bird transmission modes of H5N1 viruses. Lead–lag relationships were found among poultry and wild-bird outbreaks and human cases. Human cases were preceded by poultry outbreaks, and wild-bird outbreaks were led by human cases.
Each clade has gained its own unique spatiotemporal and genetic dominance. Genetic diversity of the H5N1 virus decreased significantly between 1996 and 2011; presumably under strong selective pressure of vaccination. Mean evolutionary rates of H5N1 virus increased after vaccination was adopted in China.
AI transmission risks: Analysis of biosecurity measures and contact structureHarm Kiezebrink
Contacts between people, equipment and vehicles prior and during outbreak situations are critical to determine the possible source of infection of a farm. Hired laborers are known to play a big role in interconnecting farms. Once a farm is infected, culling entire flock is the only option to prevent further spreading with devastating consequences for the industry.
In this paper, based on the HPAI outbreak in Holland 2003, the researchers found that 32 farms hired external labor of which seven accessed other poultry on the same day.
However, they were not the only ‘connectors’ as some (twelve) farmers also reported themselves helping on other poultry farms.
Furthermore, 27 farms had family members visiting poultry or poultry-related businesses of which nine entered poultry houses during those visits. The other enhancing factor of farm interconnections was the reported ownership of multiple locations for ten of the interviewed farms and the reported on-premises sale of farm products on one pullet and eight layer farms.
Also worth mentioning is the practice of a multiple age system reported on eight of the interviewed farms as this may increase the risk of infecting remaining birds when off-premises poultry movements occur.
AI viruses may be introduced into poultry from reservoirs such as aquatic wild birds but the mechanisms of their subsequent spread are partially unclear. Transmission of the virus through movements of humans (visitors, servicemen and farm personnel), vectors (wild birds, rodents, insects), air- (and dust-) related routes and other fomites (e.g., delivery trucks, visitors’ clothes and farm equipment) have all been hypothesized.
It is therefore hypothesized that the risk of introducing the virus to a farm is determined by the farm’s neighborhood characteristics, contact structure and its biosecurity practices.
On the one hand, neighborhood characteristics include factors such as the presence of water bodies (accessed by wild birds), the density of poultry farms (together with the number and type of birds on these farms) and poultry-related businesses and the road network. The use of manure in the farm’s vicinity is also deemed to be risky.
On the other hand, contact structure risk factors include the nature and frequency of farm visits. Therefore, a detailed analysis of the contact structure, including neighborhood risks, and biosecurity practices across different types of poultry farms and poultry-related businesses helps the improvement of intervention strategies, biosecurity protocols and adherence to these, as well as contact tracing protocols.
Farmers’ perception of visitor- and neighborhood-associated risks of virus spread is also important due to its relevance to adherence with biosecurity protocols, to contact tracing and to communicating advice to them.
Seroepidemiology for MERS coronavirus using microneutralisation and pseudopar...Ranawaka A.P.M Perera
We describe a novel spike pseudoparticle neutralisation
assay (ppNT) for seroepidemiological studies on
Middle East respiratory syndrome coronavirus (MERSCoV)
and apply this assay together with conventional
microneutralisation (MN) tests to investigate 1,343
human and 625 animal sera. The sera were collected
in Egypt as a region adjacent to areas where MERS has
been described, and in Hong Kong, China as a control
region. Sera from dromedary camels had a high prevalence
of antibody reactive to MERS-CoV by MERS NT
(93.6%) and MERS ppNT (98.2%) assay. The antibody
titres ranged up to 1,280 and higher in MN assays
and 10,240 and higher in ppNT assays. No other
investigated species had any antibody reactivity to
MERS-CoV. While seropositivity does not exclude the
possibility of infection with a closely related virus, our
data highlight the need to attempt detection of MERSCoV
or related coronaviruses in dromedary camels. The
data show excellent correlation between the conventional
MN assay and the novel ppNT assay. The newly
developed ppNT assay does not require Biosafety Level
3 containment and is thus a relatively high-throughput
assay, well suited for large-scale seroepidemiology
studies which are needed to better understand the
ecology and epidemiology of MERS-CoV.
Per contact probability of infection by Highly Pathogenic Avian InfluenzaHarm Kiezebrink
Estimates of the per-contact probability of transmission between farms of Highly Pathogenic Avian Influenza virus of H7N7 subtype during the 2003 epidemic in the Netherlands are important for the design of better control and biosecurity strategies.
We used standardized data collected during the epidemic and a model to extract data for untraced contacts based on the daily number of infectious farms within a given distance of a susceptible farm.
With these data, the ‘maximum likelihood estimation’ approach was used to estimate the transmission probabilities by the individual contact types, both traced and untraced.
The outcomes were validated against literature data on virus genetic sequences for outbreak farms. The findings highlight the need to
1) Understand the routes underlying the infections without traced contacts and
2) To review whether the contact-tracing protocol is exhaustive in relation to all the farm’s day-to-day activities and practices.
Deadly H5N1 birdflu needs just five mutations to spread easily in peopleHarm Kiezebrink
Reference: Phys.org. 15 Apr 2014. Dutch researchers have found that the virus needs only five favorable gene mutations to become transmissible through coughing or sneezing, like regular flu viruses.
World health officials have long feared that the H5N1 virus will someday evolve a knack for airborne transmission, setting off a devastating pandemic. While the new study suggests the mutations needed are relatively few, it remains unclear whether they're likely to happen outside the laboratory.
In this paper various bird welfare aspects related to avian influenza and other contagious diseases are discussed.
Disease outbreaks will, apart from the obvious direct effects on bird health, and thereby their wellbeing, also indirectly influence the welfare of the birds. For example, restrictions on outdoor access for free-range poultry may be imposed, and vaccination or testing schemes may lead to handling or sampling procedures that are stressful to the birds.
At the same time, the immediate risk of a disease outbreak may lead to improved biosecurity measures on farms, which may in turn decrease the risk of other diseases entering the premises, thus resulting in improved bird health and welfare.
Modelling wind-borne spread of HPAI between farms (2012)Harm Kiezebrink
To understand the risks of spreading contaminated materials caused by stable gassing, a quantitative understanding of the spread of contaminated farm dust between locations is a prerequisite for obtaining much-needed insight into one of the possible mechanisms of disease spread between farms.
The researchers Amos Ssematimba, Thomas J. Hagenaars, Mart C. M. de Jong of the Dutch Department of Epidemiology, Crisis Organization and Diagnostics, Central Veterinary Institute (CVI) part of Wageningen University and Research Centre, Lelystad, The Netherlands, and Quantitative Veterinary Epidemiology, Department of Animal Sciences, Wageningen University, Wageningen, The Netherland developed a model to calculate the quantity of contaminated farm-dust particles deposited at various locations downwind of a source farm and apply the model to assess the possible contribution of the wind-borne route to the transmission of Highly Pathogenic Avian Influenza virus (HPAI) during the 2003 epidemic in the Netherlands.
The model is obtained from a Gaussian Plume Model by incorporating the dust deposition process, pathogen decay, and a model for the infection process on exposed farms.
Using poultry- and avian influenza-specific parameter values we calculate the distance-dependent probability of between-farm transmission by this route.
A comparison between the transmission risk pattern predicted by the model and the pattern observed during the 2003 epidemic reveals that the wind-borne route alone is insufficient to explain the observations although it could contribute substantially to the spread over short distance ranges, for example, explaining 24% of the transmission over distances up to 25 km.
Different environmental drivers of H5N1 outbreaks in poultry and wild birdsHarm Kiezebrink
Different environmental drivers operate on HPAI H5N1 outbreaks in poultry and wild birds in Europe. The probability of HPAI H5N1 outbreaks in poultry increases in areas with a higher human population density and a shorter distance to lakes or wetlands.
This reflects areas where the location of farms or trade areas and habitats for wild birds overlap. In wild birds, HPAI H5N1 outbreaks mostly occurred in areas with increased NDVI and lower elevations, which are typically areas where food and shelter for wild birds are available. The association with migratory flyways has also been found in the intra-continental spread of the low pathogenic avian influenza virus in North American wild birds. These different environmental drivers suggest that different spread mechanisms operate.
Disease might spread to poultry via both poultry and wild birds, through direct (via other birds) or indirect (e.g. via contaminated environment) infection. Outbreaks in wild birds are mainly caused by transmission via wild birds alone, through sharing foraging areas or shelters. These findings are in contrast with a previous study, which did not find environmental differences between disease outbreaks in poultry and wild birds in Europe.
Supplementary information wind mediated transmission HPAIHarm Kiezebrink
A comparison between the transmission risk pattern predicted by the model and the pattern observed during the 2003 epidemic reveals that the wind-borne route alone is insufficient to explain the observations although it could contribute substantially to the spread over short distance ranges, for example, explaining 24% of the transmission over distances up to 25 km.
In this generic overview, you will find the date used in the publication “Modelling the Wind-Borne Spread of Highly Pathogenic Avian Influenza Virus between Farms”, published February 2012 (http://n2gf.com/?p=2377). For the outbreak of avian influenza A(H7N7) in the Netherlands in 2003, much data are available. The overview gives a description of the data used in the analyses of the mentioned publication:
Epidemiological data
There were 5360 poultry farms in the Netherlands in 2003, for all of which geographical information x is available. For 1531 farms the flocks were culled, for all of these the date of culling Tcull is known. For 227 of the 241 infected farms the date of infection tinf has been estimated, based on mortality data. The remaining 14 farms are hobby farms, defined as farms with less than 300 animals, for which no mortality data are available.
The geographic and temporal data together have previously been used to estimate the critical farm density, i.e. above what density of farms outbreaks are can occur.
Genetic data
The HA, NA and PB2 genes of viral samples from 231 farms have previously been sequenced. Sequence data RNA can be found in the GISAID database under accession numbers EPI ISL 68268-68352, EPI ISL 82373-82472 and EPI ISL 83984-84031. These data have previously been used to give general characteristics of the outbreak, to reconstruct the transmission tree and to assess the public health threat due to mutations of the virus in the animal host.
Meteorological data
Available meteorological data include wind speed wv and direction wdir (with a ten degree precision) and the fraction of time r without precipitation for every hour of every day of the outbreak, measured at five weather stations close to the infected farms. These data are available from the Royal Dutch Meteorological Institute at www.knmi.nl.
The misunderstood epidemiological determinants of covid 19, problems and solu...Bhoj Raj Singh
COVID-19, a viral disease, fought with political means for socio-economic gains, will keep on haunting humanity for long. Without doing any epidemiological study on COVID-19 we have determined its modulators and determinants not to win over COVID-19 but to create misunderstanding to persist for long in inquisitive minds to blur the vision for novel inventions. This presentation deals with COVID-19 in general and misunderstood disease determinants in particular to suggest possible means to win over the disease. As the tip of COVID-19 iceberg is illusion and reality unknown, thus the struggle is endless.
The prevalence of tuberculosis and Rifampicin-resistant tuberculosis (RMP-TB) among patients showing symptoms of tuberculosis that visited Federal Medical Centre, Yenagoa, Bayelsa state, Nigeria was determined from June 2015 to December 2015. A total of 456 patients comprising 218(47.8%) males and 238(52.2%) females were examined using their sputum and gastric lavage samples. GeneXpert System was used to determine the TB and RMF-TB. Results showed that out of the 456 patients, overall tuberculosis prevalence was 88(19.3%), males recorded 48(10.5%) while females had 40(8.8%). The highest tuberculosis prevalence was recorded amongst 21-30 years and 31-40 years age groups (5.5%). Out of the 456 patients, total prevalence for Rifampicin resistance was 11(2.4%). Of these, females and male prevalence was 6(1.3%) and 5(1.1%) respectively. There was no significant difference (P>0.05) in prevalence between age and gender. The treatment and follow-up of existing cases is a key to preventing the spread of multi drug-resistant tuberculosis.
Livestock disease drivers, ecology and pathogen evolutionEFSA EU
Presentation of the EFSA's second scientific conference, held on 14-16 October 2015 in Milan, Italy.
DRIVERS FOR EMERGING ISSUES IN ANIMAL AND PLANT HEALTH
Influenza in birds is caused by infection with viruses of the family Orthomyxoviridae placed in the genus influenza virus A. Influenza A viruses are the only orthomyxoviruses known to naturally affect birds. Many species of birds have been shown to be susceptible to infection with influenza A viruses; aquatic birds form a major reservoir of these viruses, and the overwhelming majority of isolates have been of low pathogenicity (low virulence) for chickens and turkeys. Influenza A viruses have antigenically related nucleocapsid and matrix proteins, but are classified into subtypes on the basis of their haemagglutinin (H) and neuraminidase (N) antigens (World Health Organization Expert Committee, 1980). At present, 16 H subtypes (H1–H16) and 9 N subtypes (N1–N9) are recognised with proposed new subtypes (H17, H18) for influenza A viruses from bats in Guatemala (Swayne et al., 2013; Tong et al., 2012; 2013). To date, naturally occurring highly pathogenic influenza A viruses that produce acute clinical disease in chickens, turkeys and other birds of economic importance have been associated only with the H5 and H7 subtypes. Most viruses of the H5 and H7 subtype isolated from birds have been of low pathogenicity for poultry. As there is the risk of a H5 or H7 virus of low pathogenicity (H5/H7 low pathogenicity avian influenza [LPAI]) becoming highly pathogenic by mutation, all H5/H7 LPAI viruses from poultry are notifiable to OIE. In addition, all high pathogenicity viruses from poultry and other birds, including wild birds, are notifiable to the OIE.
EFSA Opinion on electrical requirements for poultry waterbath stunning equipm...Harm Kiezebrink
In July 2014, EFSA provided her opinion on a study that proposes parameters for poultry electrical waterbath stunning different to those laid down in Council Regulation EU 1099/2009 on the protection of animals at the time of killing.
The submitted study reports upon the use (mean + SD) of a current of 104.00 ± 3.88 mA, a voltage of 125.86 ± 3.28 V and a frequency of 589.78 ± 0.63 Hz using a square wave in alternating current (AC) with a 50 % duty cycle. These conditions were applied for 15 seconds to chickens under laboratory and slaughterhouse conditions.
The methodology and the data reported do not provide conclusive evidence that the combination of the proposed electrical frequency and current induced unconsciousness without exposing the chickens to avoidable pain and suffering, and some chickens did not remain unconscious for a sufficient time to prevent avoidable pain and suffering during slaughter.
EFSA stated in their report that it was doubtful that recovery of consciousness could be avoided prior to neck cutting and/or during bleeding. The minimum duration of unconsciousness was reported to be 11 seconds, which is too short to permit a feasible stun-to-stick interval. Further, it is also doubtful that recovery of consciousness could be avoided prior to neck cutting and/or during bleeding. The minimum time to resumption of breathing was reported to be 8 seconds following stunning.
Because the information provided in the study was incomplete and insufficient, it did not pass the eligibility phase of the assessment. The information provided was sufficient to conclude that the birds were not rendered immediately unconscious by the intervention. Application of a current less than that required inducing immediate unconsciousness causes pain, distress and suffering. The study failed to demonstrate absence of pain and suffering until onset of unconsciousness. The minimum duration of unconsciousness was too short to ensure unconsciousness until death by bleeding.
OIE terrestrial code killing of animals for disease preventionHarm Kiezebrink
The guidelines are intended to help countries identify priorities, objectives and the desired goal of disease control programmes.
Disease control programmes are often established with the aim of eventual eradication of agents at a country, zone or compartment level. While this approach is desirable, the needs of stakeholders may require a broader range of outcomes.
For some diseases, eradication may not be economically or practically feasible and options for sustained mitigation of disease impacts may be needed.
AI transmission risks: Analysis of biosecurity measures and contact structureHarm Kiezebrink
Contacts between people, equipment and vehicles prior and during outbreak situations are critical to determine the possible source of infection of a farm. Hired laborers are known to play a big role in interconnecting farms. Once a farm is infected, culling entire flock is the only option to prevent further spreading with devastating consequences for the industry.
In this paper, based on the HPAI outbreak in Holland 2003, the researchers found that 32 farms hired external labor of which seven accessed other poultry on the same day.
However, they were not the only ‘connectors’ as some (twelve) farmers also reported themselves helping on other poultry farms.
Furthermore, 27 farms had family members visiting poultry or poultry-related businesses of which nine entered poultry houses during those visits. The other enhancing factor of farm interconnections was the reported ownership of multiple locations for ten of the interviewed farms and the reported on-premises sale of farm products on one pullet and eight layer farms.
Also worth mentioning is the practice of a multiple age system reported on eight of the interviewed farms as this may increase the risk of infecting remaining birds when off-premises poultry movements occur.
AI viruses may be introduced into poultry from reservoirs such as aquatic wild birds but the mechanisms of their subsequent spread are partially unclear. Transmission of the virus through movements of humans (visitors, servicemen and farm personnel), vectors (wild birds, rodents, insects), air- (and dust-) related routes and other fomites (e.g., delivery trucks, visitors’ clothes and farm equipment) have all been hypothesized.
It is therefore hypothesized that the risk of introducing the virus to a farm is determined by the farm’s neighborhood characteristics, contact structure and its biosecurity practices.
On the one hand, neighborhood characteristics include factors such as the presence of water bodies (accessed by wild birds), the density of poultry farms (together with the number and type of birds on these farms) and poultry-related businesses and the road network. The use of manure in the farm’s vicinity is also deemed to be risky.
On the other hand, contact structure risk factors include the nature and frequency of farm visits. Therefore, a detailed analysis of the contact structure, including neighborhood risks, and biosecurity practices across different types of poultry farms and poultry-related businesses helps the improvement of intervention strategies, biosecurity protocols and adherence to these, as well as contact tracing protocols.
Farmers’ perception of visitor- and neighborhood-associated risks of virus spread is also important due to its relevance to adherence with biosecurity protocols, to contact tracing and to communicating advice to them.
Seroepidemiology for MERS coronavirus using microneutralisation and pseudopar...Ranawaka A.P.M Perera
We describe a novel spike pseudoparticle neutralisation
assay (ppNT) for seroepidemiological studies on
Middle East respiratory syndrome coronavirus (MERSCoV)
and apply this assay together with conventional
microneutralisation (MN) tests to investigate 1,343
human and 625 animal sera. The sera were collected
in Egypt as a region adjacent to areas where MERS has
been described, and in Hong Kong, China as a control
region. Sera from dromedary camels had a high prevalence
of antibody reactive to MERS-CoV by MERS NT
(93.6%) and MERS ppNT (98.2%) assay. The antibody
titres ranged up to 1,280 and higher in MN assays
and 10,240 and higher in ppNT assays. No other
investigated species had any antibody reactivity to
MERS-CoV. While seropositivity does not exclude the
possibility of infection with a closely related virus, our
data highlight the need to attempt detection of MERSCoV
or related coronaviruses in dromedary camels. The
data show excellent correlation between the conventional
MN assay and the novel ppNT assay. The newly
developed ppNT assay does not require Biosafety Level
3 containment and is thus a relatively high-throughput
assay, well suited for large-scale seroepidemiology
studies which are needed to better understand the
ecology and epidemiology of MERS-CoV.
Per contact probability of infection by Highly Pathogenic Avian InfluenzaHarm Kiezebrink
Estimates of the per-contact probability of transmission between farms of Highly Pathogenic Avian Influenza virus of H7N7 subtype during the 2003 epidemic in the Netherlands are important for the design of better control and biosecurity strategies.
We used standardized data collected during the epidemic and a model to extract data for untraced contacts based on the daily number of infectious farms within a given distance of a susceptible farm.
With these data, the ‘maximum likelihood estimation’ approach was used to estimate the transmission probabilities by the individual contact types, both traced and untraced.
The outcomes were validated against literature data on virus genetic sequences for outbreak farms. The findings highlight the need to
1) Understand the routes underlying the infections without traced contacts and
2) To review whether the contact-tracing protocol is exhaustive in relation to all the farm’s day-to-day activities and practices.
Deadly H5N1 birdflu needs just five mutations to spread easily in peopleHarm Kiezebrink
Reference: Phys.org. 15 Apr 2014. Dutch researchers have found that the virus needs only five favorable gene mutations to become transmissible through coughing or sneezing, like regular flu viruses.
World health officials have long feared that the H5N1 virus will someday evolve a knack for airborne transmission, setting off a devastating pandemic. While the new study suggests the mutations needed are relatively few, it remains unclear whether they're likely to happen outside the laboratory.
In this paper various bird welfare aspects related to avian influenza and other contagious diseases are discussed.
Disease outbreaks will, apart from the obvious direct effects on bird health, and thereby their wellbeing, also indirectly influence the welfare of the birds. For example, restrictions on outdoor access for free-range poultry may be imposed, and vaccination or testing schemes may lead to handling or sampling procedures that are stressful to the birds.
At the same time, the immediate risk of a disease outbreak may lead to improved biosecurity measures on farms, which may in turn decrease the risk of other diseases entering the premises, thus resulting in improved bird health and welfare.
Modelling wind-borne spread of HPAI between farms (2012)Harm Kiezebrink
To understand the risks of spreading contaminated materials caused by stable gassing, a quantitative understanding of the spread of contaminated farm dust between locations is a prerequisite for obtaining much-needed insight into one of the possible mechanisms of disease spread between farms.
The researchers Amos Ssematimba, Thomas J. Hagenaars, Mart C. M. de Jong of the Dutch Department of Epidemiology, Crisis Organization and Diagnostics, Central Veterinary Institute (CVI) part of Wageningen University and Research Centre, Lelystad, The Netherlands, and Quantitative Veterinary Epidemiology, Department of Animal Sciences, Wageningen University, Wageningen, The Netherland developed a model to calculate the quantity of contaminated farm-dust particles deposited at various locations downwind of a source farm and apply the model to assess the possible contribution of the wind-borne route to the transmission of Highly Pathogenic Avian Influenza virus (HPAI) during the 2003 epidemic in the Netherlands.
The model is obtained from a Gaussian Plume Model by incorporating the dust deposition process, pathogen decay, and a model for the infection process on exposed farms.
Using poultry- and avian influenza-specific parameter values we calculate the distance-dependent probability of between-farm transmission by this route.
A comparison between the transmission risk pattern predicted by the model and the pattern observed during the 2003 epidemic reveals that the wind-borne route alone is insufficient to explain the observations although it could contribute substantially to the spread over short distance ranges, for example, explaining 24% of the transmission over distances up to 25 km.
Different environmental drivers of H5N1 outbreaks in poultry and wild birdsHarm Kiezebrink
Different environmental drivers operate on HPAI H5N1 outbreaks in poultry and wild birds in Europe. The probability of HPAI H5N1 outbreaks in poultry increases in areas with a higher human population density and a shorter distance to lakes or wetlands.
This reflects areas where the location of farms or trade areas and habitats for wild birds overlap. In wild birds, HPAI H5N1 outbreaks mostly occurred in areas with increased NDVI and lower elevations, which are typically areas where food and shelter for wild birds are available. The association with migratory flyways has also been found in the intra-continental spread of the low pathogenic avian influenza virus in North American wild birds. These different environmental drivers suggest that different spread mechanisms operate.
Disease might spread to poultry via both poultry and wild birds, through direct (via other birds) or indirect (e.g. via contaminated environment) infection. Outbreaks in wild birds are mainly caused by transmission via wild birds alone, through sharing foraging areas or shelters. These findings are in contrast with a previous study, which did not find environmental differences between disease outbreaks in poultry and wild birds in Europe.
Supplementary information wind mediated transmission HPAIHarm Kiezebrink
A comparison between the transmission risk pattern predicted by the model and the pattern observed during the 2003 epidemic reveals that the wind-borne route alone is insufficient to explain the observations although it could contribute substantially to the spread over short distance ranges, for example, explaining 24% of the transmission over distances up to 25 km.
In this generic overview, you will find the date used in the publication “Modelling the Wind-Borne Spread of Highly Pathogenic Avian Influenza Virus between Farms”, published February 2012 (http://n2gf.com/?p=2377). For the outbreak of avian influenza A(H7N7) in the Netherlands in 2003, much data are available. The overview gives a description of the data used in the analyses of the mentioned publication:
Epidemiological data
There were 5360 poultry farms in the Netherlands in 2003, for all of which geographical information x is available. For 1531 farms the flocks were culled, for all of these the date of culling Tcull is known. For 227 of the 241 infected farms the date of infection tinf has been estimated, based on mortality data. The remaining 14 farms are hobby farms, defined as farms with less than 300 animals, for which no mortality data are available.
The geographic and temporal data together have previously been used to estimate the critical farm density, i.e. above what density of farms outbreaks are can occur.
Genetic data
The HA, NA and PB2 genes of viral samples from 231 farms have previously been sequenced. Sequence data RNA can be found in the GISAID database under accession numbers EPI ISL 68268-68352, EPI ISL 82373-82472 and EPI ISL 83984-84031. These data have previously been used to give general characteristics of the outbreak, to reconstruct the transmission tree and to assess the public health threat due to mutations of the virus in the animal host.
Meteorological data
Available meteorological data include wind speed wv and direction wdir (with a ten degree precision) and the fraction of time r without precipitation for every hour of every day of the outbreak, measured at five weather stations close to the infected farms. These data are available from the Royal Dutch Meteorological Institute at www.knmi.nl.
The misunderstood epidemiological determinants of covid 19, problems and solu...Bhoj Raj Singh
COVID-19, a viral disease, fought with political means for socio-economic gains, will keep on haunting humanity for long. Without doing any epidemiological study on COVID-19 we have determined its modulators and determinants not to win over COVID-19 but to create misunderstanding to persist for long in inquisitive minds to blur the vision for novel inventions. This presentation deals with COVID-19 in general and misunderstood disease determinants in particular to suggest possible means to win over the disease. As the tip of COVID-19 iceberg is illusion and reality unknown, thus the struggle is endless.
The prevalence of tuberculosis and Rifampicin-resistant tuberculosis (RMP-TB) among patients showing symptoms of tuberculosis that visited Federal Medical Centre, Yenagoa, Bayelsa state, Nigeria was determined from June 2015 to December 2015. A total of 456 patients comprising 218(47.8%) males and 238(52.2%) females were examined using their sputum and gastric lavage samples. GeneXpert System was used to determine the TB and RMF-TB. Results showed that out of the 456 patients, overall tuberculosis prevalence was 88(19.3%), males recorded 48(10.5%) while females had 40(8.8%). The highest tuberculosis prevalence was recorded amongst 21-30 years and 31-40 years age groups (5.5%). Out of the 456 patients, total prevalence for Rifampicin resistance was 11(2.4%). Of these, females and male prevalence was 6(1.3%) and 5(1.1%) respectively. There was no significant difference (P>0.05) in prevalence between age and gender. The treatment and follow-up of existing cases is a key to preventing the spread of multi drug-resistant tuberculosis.
Livestock disease drivers, ecology and pathogen evolutionEFSA EU
Presentation of the EFSA's second scientific conference, held on 14-16 October 2015 in Milan, Italy.
DRIVERS FOR EMERGING ISSUES IN ANIMAL AND PLANT HEALTH
Influenza in birds is caused by infection with viruses of the family Orthomyxoviridae placed in the genus influenza virus A. Influenza A viruses are the only orthomyxoviruses known to naturally affect birds. Many species of birds have been shown to be susceptible to infection with influenza A viruses; aquatic birds form a major reservoir of these viruses, and the overwhelming majority of isolates have been of low pathogenicity (low virulence) for chickens and turkeys. Influenza A viruses have antigenically related nucleocapsid and matrix proteins, but are classified into subtypes on the basis of their haemagglutinin (H) and neuraminidase (N) antigens (World Health Organization Expert Committee, 1980). At present, 16 H subtypes (H1–H16) and 9 N subtypes (N1–N9) are recognised with proposed new subtypes (H17, H18) for influenza A viruses from bats in Guatemala (Swayne et al., 2013; Tong et al., 2012; 2013). To date, naturally occurring highly pathogenic influenza A viruses that produce acute clinical disease in chickens, turkeys and other birds of economic importance have been associated only with the H5 and H7 subtypes. Most viruses of the H5 and H7 subtype isolated from birds have been of low pathogenicity for poultry. As there is the risk of a H5 or H7 virus of low pathogenicity (H5/H7 low pathogenicity avian influenza [LPAI]) becoming highly pathogenic by mutation, all H5/H7 LPAI viruses from poultry are notifiable to OIE. In addition, all high pathogenicity viruses from poultry and other birds, including wild birds, are notifiable to the OIE.
EFSA Opinion on electrical requirements for poultry waterbath stunning equipm...Harm Kiezebrink
In July 2014, EFSA provided her opinion on a study that proposes parameters for poultry electrical waterbath stunning different to those laid down in Council Regulation EU 1099/2009 on the protection of animals at the time of killing.
The submitted study reports upon the use (mean + SD) of a current of 104.00 ± 3.88 mA, a voltage of 125.86 ± 3.28 V and a frequency of 589.78 ± 0.63 Hz using a square wave in alternating current (AC) with a 50 % duty cycle. These conditions were applied for 15 seconds to chickens under laboratory and slaughterhouse conditions.
The methodology and the data reported do not provide conclusive evidence that the combination of the proposed electrical frequency and current induced unconsciousness without exposing the chickens to avoidable pain and suffering, and some chickens did not remain unconscious for a sufficient time to prevent avoidable pain and suffering during slaughter.
EFSA stated in their report that it was doubtful that recovery of consciousness could be avoided prior to neck cutting and/or during bleeding. The minimum duration of unconsciousness was reported to be 11 seconds, which is too short to permit a feasible stun-to-stick interval. Further, it is also doubtful that recovery of consciousness could be avoided prior to neck cutting and/or during bleeding. The minimum time to resumption of breathing was reported to be 8 seconds following stunning.
Because the information provided in the study was incomplete and insufficient, it did not pass the eligibility phase of the assessment. The information provided was sufficient to conclude that the birds were not rendered immediately unconscious by the intervention. Application of a current less than that required inducing immediate unconsciousness causes pain, distress and suffering. The study failed to demonstrate absence of pain and suffering until onset of unconsciousness. The minimum duration of unconsciousness was too short to ensure unconsciousness until death by bleeding.
OIE terrestrial code killing of animals for disease preventionHarm Kiezebrink
The guidelines are intended to help countries identify priorities, objectives and the desired goal of disease control programmes.
Disease control programmes are often established with the aim of eventual eradication of agents at a country, zone or compartment level. While this approach is desirable, the needs of stakeholders may require a broader range of outcomes.
For some diseases, eradication may not be economically or practically feasible and options for sustained mitigation of disease impacts may be needed.
Dossier Vaccination: what causes poultry vaccination to failHarm Kiezebrink
This is the third presentation on vaccination, posted recently by Dr. Ossama Motawae, an Egyptian veterinarian. In this presentation, he explains what causes vaccination programs to fail. An interesting presentation for those who are not so familiar with the day-to-day practice of poultry vaccination.
The poultry industry in China is dominated by chicken production which comprises 70 to 80 percent of all poultry production. On a macro level, by 2011 the country was already the second largest producer of poultry meat and eggs in the world and the size of the industry continues to expand.
This report tracks the growth of the Chinese poultry industry during the past three decades and the implications of this development. China’s poultry industry is going through rapid industrialization, characterized by intensification of farming, horizontal consolidation and vertical integration.
Both the size of the industry and changes in poultry production practices (in conjunction with development in the livestock sector as a whole) have significant implications for public health, the environment, rural livelihoods and animal welfare.
Although the helminth parasites of domestic hogs are well documented worldwide, no information is available about the digestive and pulmonary helminth infections of wild boar in Morocco. The lungs of 33 wild boars (Sus scrofa barbarus) (19 females and 14 males) from four area of El Hajeb province (Middle Atlas) hunted officially for wildlife damage control, from October 2014 to March 2015 were examined for lung nematodes. Twenty eight out of 33 wild baors, (84.4%) were positive for three species of Metastrongylus and their prevalence was as follows: Metastrongylus pudendotectus (84.4%), Metastrongylus confusus (72.7%) and Metastrongylus salmi (51.5%). In most cases, multi-species infection was observed. Prevalence and infection intensity were found greater in juvenile females less than 1 year old than in adults and males. Prevalence and intensity of infection were higher in wild boars collected from range lands and forest than in wild boars collected in the cultivate area. Further studies are needed to understand the factors structuring Metstrongylidae communites
Presentation bumpsa 2015-symposium - effect of global travel on health _ the ...Gordon Takop Nchanji
The aim of the presentation was to create awareness about the interaction between health and travel. Here, particular emphasis is on infectious diseases. Read and digest. Comments are welcomed.
Study of the Seroprevalence of Anti-Leptospirosis Antibodies in Subjects in T...IIJSRJournal
Leptospirosis is a tropical and subtropical zoonotic disease culminating as a serious public health problem worldwide, apparently existing as co-infections with various other unrelated diseases, such as malaria. It is caused by spiral bacteria and the main vectors of which are rodents. These bacteria have various survival mechanisms in the environment allowing them to carry out their infectious cycle within their host organisms. The pathophysiological mechanisms pertaining to leptospirosis is still not understood in full and mis or underdiagnosed.
A cross-sectional descriptive study was carried out in three different localities in Niamey where respondents were screened for to demonstrate transmission to humans. Indirect ELISA method as a laboratory diagnostic or screening toll is used by utilizing leptospiral-specific IgG from serum samples of the respondents.
Results from the study showed that 11 people are found to be positive for leptospirosis (with a seroprevalence of 2.75%) with a strong tendency in the slaughterhouse workers which presents a fairly high risk compared to the other localities of the study. Indeed, the different areas/localities of this pilot study do not present the same level of risk because they are not subject to the same risk associated factors. In this vein, we have 87.6% of population exposed to the presence of rats, 48% are in contact with animals, 38.6% live in homes near water and 12.9% go swimming.
This study made it possible, on the one hand, to highlight the transmission of leptospirosis from animals to humans and, on the other hand, to draw attention to the involvement of the various identified risk factors.
Corona virus current scenario (theoretical outlook)Dr. sreeremya S
Corona virus(COVID-19) is RNA virus. Which has proved to be pandemic.It causes respiratory disease called Severe Acute Respiratory Syndrome(SARS). Currently it is a deadly disease which is killing hundreds of people day by day from late 2019 to till date. There is only few studies regarding the corona virus infection in animals. Studies are still progressing to find remedies like variolation, RNA silencing or boosting human interferon’s to decrease the affect of the disease.
The Parity Rate of Indoor-Resting Adult Female Anopheles and Culex Mosquitoes...IJEAB
A study on the parity rate of indoor-resting Anopheles and Culex mosquitoes and their implication in disease transmission was carried out in Nnamdi Azikiwe University female hostel between June and July 2016. The mosquitoes were sampled weekly from 24 randomly selected rooms using pyrethrum knock-down collection (P.K.C). A total of 516 mosquitoes comprising of 4 species: Anopheles gambiae, Anopheles funestus, Culex quinquefasciatus and Culex annulioris, were collected during the study period. The mosquitoes were examined for their abdominal gradings/gonotrophic stages and dissected for parity determination. Culex quinquefasciatus (61.43%) constituted the most abundant species followed by Anopheles gambiae (30.04%) and Anopheles funestus (7.56%) and the least being Culex annulioris (0.97%). Results showed that majority of the vector species were fed and parous and variations among the parity rates of the 4 species was significant (P <0.05). The high rate of the fed and parous mosquito species is of utmost concern in the hostel environment and therefore control measures aimed at eliminating the breeding sites and reducing its contact with the students should be embraced and practiced so as to minimize disease transmission among the students.
Preparedness, Prediction and Prevention of Emerging Zoonotic Viruses with Pan...Global Risk Forum GRFDavos
Presentation at 3rd GRF One Health Summit 2015
The One Health Approach for Communicable Diseases
Sylvie VAN DER WERF, Institut Pasteur, France, on behalf of the PREDEMICS consortium
Knowledge, attitudes and practices of Lassa fever in and around Lafia, Centra...Premier Publishers
This descriptive cross-sectional study assessed the knowledge, attitudes and practices of Lassa fever in and around Lafia, Central Nigeria. Structured questionnaires were administered to 200 consenting respondents from urban and sub-urban areas in Lafia. Of the 200 respondents, 87% heard of Lassa fever with 89% and 80% from urban and sub-urban areas. There was no significant difference on the awareness of Lassa fever among respondents from urban and sub-urban areas (P>0.05). There was misperception about species affected and modes of transmission of the disease, nevertheless bleeding was mentioned by 39% of the respondents as the major clinical manifestation. Also, 83% of the respondents had rats/rodents in and around their residence, of which 28% come into contact with urine/feaces of the rodents and 24% consume foods contaminated by the rodents. However, 85% of the respondents do not believe in the existence of Lassa fever. Most respondents (41%) reported that they will show some discriminatory attitudes towards individuals suspected or having Lassa fever. Furthermore, 67% of the respondents were optimistic to accept possible vaccine candidate against the disease. Public health awareness especially among the sub-urban dwellers should be intensified so as to reduce the spread of both the vector and the virus.
Avian Influenza H7N9
Winnifred Brefo-kesse
Hlth 626
March 31, 2019
Professor Hughes
Part I: THE SITUATION ASSESSMENT
In February and March 2013, a novel influenza A (H7N9) virus emerged in China, causing an acute respiratory distress syndrome and occasionally multiple organ failure with high fatality rates in humans (Li et al., 2014). A total of 681 laboratory-confirmed cases and 275 deaths have been reported as of November 13th, 2015, with a fatality rate of 40% (http://www.who.int/influenza/human_animal_interface/HAI_Risk_Assessment/en/). H7N9 has been evolving and established amongst chickens in China over the past two years with occasional human infections (Lam et al., 2015; Su et al., 2015), thus posing a threat to public health. In the absence of an annually-updated effective vaccine, antiviral drugs constitute the first line of defense against H7N9 infections. H7N9 viruses already possess natural resistance to M2-ion channel blockers (amantadine and rimantadine) when it first emerged in 2013 (Gao et al., 2013). Therefore, neuraminidase inhibitors (NAIs), which include oseltamivir (TamifluH), zanamivir (RelenzaH) and peramivir constitute the main antiviral drugs against H7N9 infections (Hu et al., 2013; Wu et al., 2013). However, treatment with NAIs against H7N9 infections has resulted in the emergence of drug-resistant mutant viruses, as soon as 1~9 days after administration (Gao et al., 2013; Hu et al., 2013). Moreover, the first H7N9 isolate (A/Shanghai/1/2013(H7N9), SH-H7N9) was resistant to oseltamivir (Gao et al., 2013). Avian influenza A H7 viruses are a group of viruses that is mostly found amongst birds. The H7N9 virus is a subgroup of the H7 viruses and was recently discovered in China. There were three cases discovered in March of 2013 which ultimately increased in May by 132 cases. Of those cases, the 39 infected, died because of the virus (Peipei Song1, 2013). The clinical features described in the three patients with H7N9 virus infection, included fulminant pneumonia, respiratory failure, acute respiratory distress syndrome (ARDS), septic shock, multi-organ failure, rhabdomyolysis, and encephalopathy, are very troubling (Timothy M. Uyeki, 2013). As of now, this virus has reached stage two of three which is poultry passing the virus to humans. There is one more stage left which is human to human transmission which the Chinese health officials have confirmed it is not yet occurring. Creating an anti-virus takes a lot of time and until then public health officials should create new tactics in battling this epidemic.
Since there isn’t an anti-virus for the H7N9 virus, different health policies must be put in place to control the outbreak as well as preventative strategies from escalating. This vir.
Human Noroviruses (HuNoVs) are important enteric pathogens, which affect the stomach and intestines, leading to
gastroenteritis or more commonly called the "stomach flu" or “winter vomiting bug". HuNoVs are mainly transmitted by the fecal-oral
route, either by directly infected person-to-person contact or directly via contaminated foods, water and surface areas. The virus is highly
contagious as 10-100 virus particles are sufficient to cause diseases. HuNoVs can spread easily and cause prolonged outbreaks. This is
due to their environmental persistence, high infectivity, being resistance to disinfection and difficulty in preventing transmission.
HuNoVs are the most common causative agent leading to acute gastroenteritis among infectious diseases worldwide and poses a serious
public health problem, especially among children being the most susceptible. In developing countries, the highest cost of medical care
after respiratory infections is listed for acute gastroenteritis. In this study, Norovirus outbreaks, precautions, its identification and
struggles were informed and some suggestions were made about this case.
FLI Seminar on different response strategies: Stamping out or NeutralizationHarm Kiezebrink
During this spring, American poultry producers are losing birds by the millions, due to the High Pathogenic Avian Influenza outbreaks on factory farms. USDA APHIS applied the stamping out strategy in an attempt to prevent the flu from spreading.
With stamping out as the highest priority of the response strategy, large numbers of responders are involved. With in average almost 1 million caged layers per farm in Iowa, there is hardly any room for a proper bio security training for these responders. And existing culling techniques had insufficient capacity, the authorities had to decide to apply drastic techniques like macerating live birds in order to take away the source of virus reproduction.
This strategy didn't work; on the contrary. Instead of slowing down the spreading of the virus, the outbreaks continue to reoccur and have caused death and destruction in 15 USA states, killing almost 50 million birds on mote than 220infected commercial poultry farms, all within a very small time frame.
The question is whether the priority of the response strategy should be on neutralizing the transmission routes instead of on stamping out infections after they occur. All indicators currently point out into the direction that the industry should prioritize on environmental drivers: the connection between outbreaks and wild ducks; wind-mediated transmission; pre-contact probability; on-farm bio security; transmission via rodents etc.
Once the contribution of each transmission route has been determined, a revolutionary new response strategy can be developed based on the principle of neutralizing transmission routes. Neutralizing risks means that fully new techniques need to be developed, based on culling the animals without human – to – animal contact; integrating detergent application into the culling operations; combining culling & disposal into one activity.
This new response strategy will be the main subject of the FLI Animal Welfare and Disease Control Seminar, organized at September 23, 2015 in Celle, Germany
Low Atmospheric Pressure Stunning is not a humane alternative to Carbon Dioxi...Harm Kiezebrink
I would like express gratitude to the HSA for their 20 years of tireless advocacy for improving pigs' welfare. Their efforts have empowered those seeking alternatives to carbon dioxide stunning. Over nearly 30 years, I've worked on animal welfare friendly stunning applications, particularly regarding stunning/slaughtering using nitrogen foam, and I believe I've found the definitive answer.
The industry originally adopted large-scale carbon dioxide stunning to optimize food production, reduce costs, and lower meat prices, which is only feasible with parallel processing (simultaneously stunning groups of pigs) rather than serial processing (stunning each pig individually). Electrocution is not viable for large-scale operations due to this need for parallel processing. Therefore, a replacement gas that lacks carbon dioxide's detrimental properties is needed, but only a few gases are suitable.
Additionally, the application of an alternative gas must adhere to several fundamental principles:
a) Applicability of the methods for stunning and killing pigs, including their scalability for large-scale application.
b) Description of the technical.
c) Animal welfare consequences associated with specific techniques, including welfare hazards (ABMs), animal-based indicators (ABIs), preventive and corrective measures, and the sufficiency of scientific literature in describing these consequences.
d) Applicability under field conditions.
Introducing a novel application for large-scale pig slaughter is complex and time-consuming before it can be expected, especially given the substantial economic and financial impact for the industry. However, there is hope on the horizon.
The alternative gas is nitrogen, and the application is based on using high-expansion foam filled with 100% nitrogen, applied in a closed container. Within a minute, all air is displaced by the foam, after which the container is sealed, and the foam is broken down with a powerful nitrogen pulse. This ensures that the foam does not affect the stunning process; the entire process can be visually and electronically monitored, and the residual oxygen level in the container is consistently below 2%. The container dimensions are identical to the gondolas used in the globally implemented carbon dioxide gondola system.
The integration of nitrogen foam technology into European regulation EU1099/2009 is nearing completion. All scientific and technical procedures have been submitted to the EU Commission, with finalization awaiting the presentation of EFSA's scientific opinion to the Commission and subsequent approval for inclusion. This final phase is anticipated to occur during the general meeting slated for June 2024.
This marks the first step toward replacing carbon dioxide in 25 years. Fingers crossed for the EU Commission's decision in June 2024!
Harm Kiezebrink
Independent Expert
Preventief ruimen bij vogelgriep in pluimveedichte gebieden en mogelijkheden ...Harm Kiezebrink
New Risk assessment model
The applications designed for farrow-to-weaner pig farms rely on a novel risk assessment model. This model, developed from a recent study, indicates that the likelihood of an undetected infection on nearby farms notably diminishes 7 to 14 days following the identification of the source farm.
This risk assessment model is based a Dutch study that is published by T.J. Hagenaars et al on June 30, 2023: “Preventief ruimen bij vogelgriep in pluimveedichte gebieden en mogelijkheden voor aanvullende bemonstering” (Preventive culling in areas densely populated with poultry, and possibilities for additional sampling).
According to this premise, instead of the standard depopulation approach of euthanizing pigs on-site, pigs beyond the immediate vicinity of infected farms are slaughtered.
Animal Health Canada is currently evaluating new strategies and technologies for managing large-scale emergency situations involving pigs. I have been actively involved in developing strategies and procedures aimed at implementing strict control measures for pig euthanasia during emergencies, with a focus on substantially reducing costs by avoiding unnecessary culling and destruction of healthy animals.
Opting for slaughtering over on-farm euthanasia not only reduces the operational burden on farms but also repurposes the pigs as a valuable protein source rather than considering them as animal waste. This approach assists in crisis management during widespread outbreaks, significantly reduces expenses, and simultaneously mitigates risks.
While this approach is influenced by the new EU regulations implemented since May 2022, it can be adapted for implementation within the context of any EU Member state, as well as in the USA and Canada.
Managing large-scale outbreaks at Farrow-to-Weaner FarmsHarm Kiezebrink
In the face of large-scale outbreaks of swine Influenza A Virus (swIAV), there's a call for exploring various strategies conducive to managing emergencies in field conditions.
Through subdivision, a customized approach can be embraced to enhance operational efficiency and effectiveness while mitigating the impact on individual farms. This tactic maximizes emergency deployment capacity and streamlines standard procedures. Moreover, leveraging the existing capacity of farming aids in alleviating scrutiny on animal welfare standards, presenting a notable advantage.
Nitrogen filled high expansion foam in open ContainersHarm Kiezebrink
On March 31, 2023 the US National Pork Board validated a study by Todd Williams, of Pipestone Veterinary Services, based on the use of high expansion nitrogen foam for the large-scale depopulation of all classes of swine, utilizing Livetec Systems Nitrogen Foam Delivery System (NFDS).
The high expansion foam produced by the Livetec Systems NFDS surrounds the animal in large bubbles filled with nitrogen with a base expansion ration of between 300 and 350 to 1, as mentioned on the information provided by the producer of the firefighting foam.
The Livetec technology, based on using Compressed Air Foam (CAF) filled with nitrogen instead of air for depopulating pigs, emerges within a critical landscape. The complexities of implementing effective emergency depopulation strategies for livestock, particularly swine, present multifaceted challenges. Livetec's approach relies on high expansion firefighting foam, aiming to euthanize pigs by submerging them in foam.
The Livetec system's claims about the effectiveness of nitrogen-filled high expansion foam for depopulating market pigs lack substantial evidence upon analysis. The discrepancy between the actual foam produced during field trials and the promised high expansion foam, coupled with the absence of concrete proof supporting the method's efficacy, discredits the technology's claims.
World bank evaluating the economic consequences of avian influenzaHarm Kiezebrink
Pandemics cause very serious loss of life, restrictions of freedom and serious economic damage. Potential pandemics all are related to our dealing with animals, both wild and domesticated.
In this Word Bank study of 2006, the effects of a severe HPAI pandemic (with a highly pathogenic avian influenza virus crossing the species barrier and infecting humans) predicted economic losses from 2-10% of the world economy.
The economic impact of the present COVID-19 crisis, caused by the SARS-CoV2 virus spreading from wild animals to humans, probably will reach the upper limits of this prediction even if the losses of life might be near the lower limits mentioned in the report (1,4 millions rather than 71 millions).
A common observation is that governments were late to react on the COVID-19 outbreak.
Pandemics are rare, so due to cost-benefit considerations emergency preparations do usually not get beyond an advisory (paperwork) phase. When an emergency eventually arises, the response is too late, too little, and with disastrous effects on animal and/or human welfare that could have been avoided. Relatively small, short-term financial savings result in big, long-term losses.
Protection against outbreaks cannot be achieved by political decisions during a crisis. Our dealing with animals, especially in animal production, must be inherently safe so that animal health and public health are protected.
This is recognized in the One Health strategy that has been adopted internationally.
An outbreak of animal disease occurs should be contained at a very early stage. This can only be realized if all farms have their own emergency plans, with equipment to deal with contagious diseases already present at the farm.
Gas alternatives to carbon dioxide for euthanasia a piglet perspectiveHarm Kiezebrink
The use of nitrous oxide as an anesthetic/euthanasia agent may prove to be affordable, feasible and more humane than other alternatives.
The neonatal stage is a critical time in the life of a pig, when they are prone to become sick or weak. This is the stage at which most euthanasia procedures are required if the pig is judged unable to recover. Any euthanasia method should be humane, practical, economical and socially acceptable to be universally accepted.
They found that nitrous oxide in oxygen appeared to be less aversive than nitrous oxide, nitrogen, or argon all combined with low (30%) concentrations of carbon dioxide or 90% carbon dioxide by itself.
This study is the first to investigate the use of nitrous oxide at sufficiently high concentrations to cause anesthesia. Nitrous oxide, commonly referred to as laughing gas, has been widely used in human surgery and dental offices for its pain-relieving, sedative and anxiolytic effects. It is cheap, non-flammable, non-explosive, legally accessible and not classified as a drug in the U.S., and already commonly used in the food industry as a propellant for food products.
Development of its use into an automated procedure will allow producers to implement it with little effort. Thus its use as an anesthetic/euthanasia agent may prove to be affordable, feasible and more humane than other alternatives.
Anoxia: High expansion foam
The Anoxia method is unique for creating an environment without oxygen under atmospheric circumstances. High expansion foam is produced by mixing nitrogen and a mixture of water and specially developed high expansion detergent, with an expansion rate upto 1:1000, meaning that 1 litre of water/foam agent mix expands up to 1 m3 foam. Due to the specially designed foam generator, the high expansion foam bubbles are filled with a > 99% concentration of nitrogen. The oxygen level surrounding the animal drops from 21% in atmospheric air to < 1 % once the animal is submerged in the foam.
Anoxia: convulsions, but no stress or pain
The animals need a constant supply of oxygen to the brain. Applying Anoxia foam, the oxygen is replaced by nitrogen. As a result the nitrogen level is raised to > 99% and the oxygen level is lowered to < 1%. Considering the natural reaction to sudden lack of oxygen the animal is rendering quickly into unconsciousness. As a consequence, behavioral indicators like loss of posture and convulsions will appear. With this in mind, unconscious animals are insensitive to perceive unpleasant sensations like pain.
Anoxia: How Anoxia foam is created
A mixture of 97% water and 3% high expansion foam agent is sprayed into the Anoxia foam generator, creating a thin film on the outlet of the generator. At the same time, nitrogen is added with overpressure into the foam generator. The nitrogen expands when it exits the generator, creating robust high expansion foam. The high expansion foam bubbles are filled with > 99% nitrogen.
Anoxia: Single foam generator systems
In practice, one Anoxia foam generator creates a volume of up to 750 liter of high expansion foam per minute. This volume is more than sufficient to fill a wheelie-bin container within 30 seconds. The most common container volumes are: M size - 240 liter; L size - 340 liter; and XL size - 370 liter. The choice of the volume of the container depends of the size of the animal and/or the number of animals that need to be stunned/killed. A lid with a chiffon that seals the container. As soon as the foam exits the chiffon, the gas supply is stopped and the chiffon is closed. The nitrogen gas concentration in the container remains at 99%.
Although commonly used in other settings, defining animal welfare as part of a corporate CSR setting is not new.
There are many ways to define CSR. What they have in common is that CSR describes how companies manage their business processes to produce an overall positive impact on society. The phenomenon CSR is a value concept that is susceptible to particular ideological and emotional interpretations. Different organizations have framed different definitions - although there is considerable common ground between them.
Some important national players of the food chain at different steps (mainly food retailers and food services) have included animal welfare in their CSR.
The Anoxia technique is developed as alternative for existing animal stunning methods that are based on the use of CO2, electrocution, neck dislocation, captive-bolt, as well as killing methods like de-bleeding and maceration.
In the past 10 years, Wageningen University and University of Glasgow conducted several studies that proved that the technique could be applied successfully for culling poultry (Proof of Principle Anoxia Technique). This was the start of the development of several applications based on the Anoxia principle, using high expansion foam filled with >99% Nitrogen that are now introduced for:
1. Stunning and killing of sick and cripple killing piglets less than 5 kg
2. Stunning and killing of sick or cripple poultry (especially poultry > 3kg) who need to be killed on the farm by the staff for welfare purposes (avoiding unnecessary stress or pain)
3. Stunning and killing poultry that arrives on the slaughterhouse but that are unfit to be slaughtered (due to injuries occurred during transportation – providing signs of possible illness etc.)
4. Stunning and killing of male pullets at the hatchery
5. Stunning and killing of half-hatched chickens and embryos in partly-hatched eggs, before destruction
6. Stunning and killing parent stock poultry
7. Killing of animals that has been stunned (captive bolt – blow-on-the-head method, etc.) replacing killing by de-bleeding
8. Culling of ex-layers
9. Culling of poultry for disease control purposes
Last November we started the launch of the commercialization of the Anoxia applications in Holland, Germany and Sweden, focusing on the areas where a solution is most needed: piglets (< 5kg) and poultry (> 3kg) on farms.
Since November 2016, the introduction of these applications took place in Holland, Germany, Sweden and Denmark
World Health Organization director- general Margaret Chan Fung Fu-chun warns bird flu H7N9 is particularly worrying as it could be a flu pandemic strain. This is because H7N9 is unique as it does not make chickens sick but is deadly in humans. Sick birds could usually provide early warning for imminent outbreaks, Chan told The Standard. This comes as Macau reported its first human case of H7N9 yesterday. "The biggest challenge for the world is the next influenza pandemic," Chan said.
Laves presentation practical experiences in the culling of poultry in germanyHarm Kiezebrink
This presentation, based on the practical experiences in culling poultry in Germany, gives an overview of the culling techniques currently in use in Germany. It is presented by dr. Ursula Gerdes, dr. Josef Diekmann and ing. Rainer Thomes.
LAVES is the Lower Saxony State Office for Consumer Protection and Food Safety, located in Oldenburg, Germany. With around 900 employees they are entrusted with tasks in the areas of food and utensil inspection, feed inspection, meat hygiene, veterinary drug monitoring, eradication of animal diseases, disposal of animal by-products, animal welfare, ecological farming, market surveillance and technical process monitoring.
Berg et al. 2014 killing of spent laying hens using co2 in poultry barnsHarm Kiezebrink
September 2015: In Sweden, spent laying hens are killed either by traditional slaughter; on-farm with CO2 in a mobile container combined with a grinder; or with CO2 stable gassing inside the barn. The number of hens killed using the latter method has increased. During these killings a veterinarian is required to be present and report to the Swedish Board of Agriculture.
Data were registered during four commercial killings and extracted from all official veterinary reports at CO2 whole-house killings in 2008–2010. On-farm monitoring showed that temperature decreased greatly and with high variability. The time until birds became unconscious after coming into contact with the gas, based on time until loss of balance, was 3–5 min.
Veterinary reports show that 1.5 million laying hens were killed, in 150 separate instances. The most common non-compliance with legislation was failure to notify the regional animal welfare authorities prior to the killings. Six out of 150 killings were defined as animal welfare failures, eg delivery of insufficient CO2 or failure to seal buildings to achieve adequate gas concentration.
Eleven were either potentially or completely unacceptable from the perspective of animal welfare. We conclude that, on the whole, the CO2 whole-house gas killing of spent hens was carried out in accordance with the appropriate legislation. Death was achieved reliably.
However, there remain several risks to animal welfare and increased knowledge would appear vital in order to limit mistakes related to miscalculations of house volume, improper sealing or premature ventilation turn-off.
The latest outbreak of High Pathogen Avian Influenza in the USA and Canada in the spring of this year and the inability to avoid animal welfare catastrophes ultimately proves that new emergency response strategies are needed. Strategies that are based on taking away the source of infection instead of killing as many animals as possible within 24 hours, regardless the consequences.
The statement that “It’s possible that human infections with these viruses may occur” and that “these viruses have not spread easily to other people” is confusing. Humans can become infected without showing clinical signs. They can become the major carrier of the infection.
Especially during depopulation activities, viruses easily transmit through responders. Tasks like taking layers out of their cages and transport the birds manually through the narrow walkways between the cages, and disposal of infected animals are specific risks that need to be avoided. Simply switching of the electricity so that sick birds don’t have to be handled is not the solution.
Although humans are supposed to be less susceptible, they can become carrier of the virus. Only the highest level of biosecurity could prevent the transmission through the humans and materials that have been in direct contact with infected animals and materials.
Simply switching of the electricity so that sick birds don’t have to be handled is not the solution. Avoid killing animals is always the better option and in Germany, the discussion on the strategy based on neutralizing risks and is in the making. Avoiding situations demands a proactive role of the poultry industry.
Ventilation Shutdown: who takes the responsibility to flip the switch?Harm Kiezebrink
On September 18, 2015 the USA Government and the American egg producers announced that they would accept the Ventilation shutdown method as a method of mass destruction of poultry when other options, notably water-based foam and CO2, are not available for culling at the farm within 24-36 hours. This is actually the case on all caged layer farms in the USA, in particular in Iowa.
The Ventilation shutdown method consists of stopping ventilation, cutting off drinking water supply, and turning on heaters to raise the temperature in the poultry house to a level between 38 Celsius and 50 Celsius. Birds die of heat stress and by lack of oxygen in a process that easily takes over after a period of at least 3 days. Ventilation shutdown is a killing method without prior stunning of the birds, and as such is contrary to all international Animal Welfare standards.
Animal welfare specialists in disease control strongly oppose this introduction of the cruelest method of killing poultry that lost their economic value. The Humane Society (HSUS) described it as the “inhumane mass baking of live chickens”. With adequate preparation the alternative methods, like the water-based Anoxia foam method, can be available at each farm for immediate use in case of an outbreak. The ban of the Ventilation shutdown method should therefore be maintained and the Anoxia method should be further developed so that is suitable for application to caged layers and turkeys. In Germany, such a system is currently under development and will become commercially available soon.
The poultry industry in the USA ignores this development and asks for a formal approval of the Ventilation Shutdown method. Speaking on August 19, 2015, during the United Egg Producers (UEP) national briefing webinar, UEP President Chad Gregory explained that much research is being done concerning the feasibility of such a depopulation program.
“The government, the producers, the states and UEP, we all recognize that depopulation is going to have to happen faster and ideally within 24 hours.”
Quick depopulation of affected flocks is important, Gregory said, because the sooner a flock is depopulated, the risk of the virus going into fans and out into the atmosphere becomes smaller. Gregory said ventilation shutdown – if approved – would probably only be used in a worst-case scenario or when all other euthanasia options have been exhausted. Gregory did not elaborate on how to adequately prevent outbreaks and how to promote more animal-friendly methods.
In order to become one step ahead of an outbreak of high pathogen diseases like the current H5N2, the veterinary authorities need to stop the outbreak immediately after the first signals occur. Strict and thorough biosecurity measures are the most fundamental feature to protect poultry flocks on farms.
Without functional culling techniques, the options to effectively and efficiently cull in average more than 925,000 chickens per farm (in Iowa, USA) are limited: either by macerating the chickens alive – or by ventilation shut-down (closing down all ventilation, placing heaters inside the house, and heat the entire house to a temperature higher than 600 C).
Although both methods cause death of the birds, it has not been proven to be effective nor efficient. The primary goal to slowdown outbreaks and bring it to a complete stop but macerating live birds and killing them by heat stress and lack of oxygen would be against all International Animal Welfare standards.
Animal welfare specialists in disease control strongly oppose against the introduction of these most cruel methods of killing poultry and argue that the ban on these methods should be maintained and alternative methods need to be considered.
Avian Influenza in the Netherlands 2003: comparing culling methodsHarm Kiezebrink
During the outbreak of H7N7 in Holland, 29,500.000 birds were killed at the farm. This presentation compares different culling techniques, such as stable gas, container gassing and electrocution.
Risk analysis on the role of wild ducks by the introduction of Avian Influenz...Harm Kiezebrink
Lelystad, April 2015: According to a recently published study (in Dutch) by the University of Wageningen, wild ducks are are identified as a high risk factor for the introduction of Low Pathogen Avian Influenza viruses in free-range laying hens.
Through a case-control study investigated presumed risk factors for introduction of low-pathogenic avian influenza (LPAI) virus in poultry laying farms free range. Under a LPAI virus was defined in this study: an avian influenza virus of each subtype (H1 H16 tm), with the exception of the highly pathogenic avian influenza (HPAI) viruses.
In order to determin the potential risk factors for infection with LPAI virus, forty Dutch free range poultry farms where the introduction of Low Pathogen Avian Ifluenza virus has been confirmed in the past (cases) were compared with 81 free range poultry farms where no introduction has taken place (controls). Questions about the presence of potential risk factors through surveys submitted to the poultry farmers.
The analysis of the various factors shows that the risk of introduction of LPAI virus on free range laying farms 3.3 (95% CI: 1.2-9.7) times higher as mallards has identified by the farmer entering the free range area at least once a week, in comparison to free-range laying farms where wild ducks have been identified by the farmer once a month or less.
It seems logical that the regular presence of wild ducks in the free-range increases the risk exposure of the chickens LPAI virus since wild waterfowl are the natural reservoir of avian influenza viruses.
The study also revealed that the risk factor for free range layer farms located on clay is 5.8 (95% CI: 2.2-15.1) times have higher risk of introduction of LPAI virus then free range layer farms on sandy soil or a soil other than clay. The soil on which the free range farm is situated is probably an indirect risk factor (association and not causation): especially in case the farm is located near the coast or close to rivers.
Anoxia presentation during the AI symposium in Taiwan, March 2015Harm Kiezebrink
During the Symposium on managing outbreaks of Avian Influenza in Taiwan, the main subject was managing the outbreaks without breaching animal welfare during the culling operations. Although it seams impossible, this can be done using the Anoxia method (see also www.N2GF.com for more information), under the condition that the entire process is been taking into account: killing of animals, carcass disposal, transport & logistic, Occupational Health & Safety, environmental issues, pest control, contact between animals and humans: all these factors contribute to the risks of spreading. If one factor fails, the virus can escape and infect the next flock, making it needed to kill more birds. For that reason, all factors are equally important to maintain animal welfare during outbreak situations.
In a number of recently published studies, Professor Stegeman (University of Utrecht, Holland) explains that serologic spreading of viruses is related to human contacts with contaminated infected animals, carcasses, manure and materials infected/suspected animals; movements of farm labourers, products, equipment etc. Most of these contacts (and movements) take place prior, during, and after the culling procedure, whereas the quantity and the intensity of the contacts - thus this human contact/materials are decisive factors for the serologic spreading of viruses to enter farms and most likely play an important role in spreading between farms. Suspicion/infection of farm animals inevitably leads to preventive culling of all farm animals within the direct proximity. For that reason, the serologic spread of viruses has become a major animal welfare indicator that has to be taken into consideration as such.
Each culling procedure features its own unique contact pattern between animals and humans and is based on applied culling, disposal and transport technique. These contact patterns related to the specific combination of applied methods, defines the major contribution factors for spreading of infections. Therefore should the potential risks of these procedures be evaluated and rated on the art and the intensity of the potential contact between animals and humans/materials, prior, during and after the procedure.
Therefore, the entire procedure of killing, disposal and transportation is therefore considered as Major Interest, in terms of animal welfare.
Overview of recent outbreaks of H5N8-High Pathogen Avian Influenza in Europe...Harm Kiezebrink
Updated outbreak assessment on Highly Pathogenic Avian Influenza: Europe, America and the Middle East. By the DEFRA, Veterinary & Science Policy Advice Team - International Disease Monitoring.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...
Spatio temporal dynamics of global H5N1 outbreaks match bird migration patterns
1. Spatio-temporal dynamics of global H5N1 outbreaks
match bird migration patterns
Yali Si1,2,4
, Andrew K. Skidmore1,2
, Tiejun Wang1
, Willem F. de Boer2
, Pravesh Debba3
,
Albert G. Toxopeus1
, Lin Li4
, Herbert H.T. Prins2
1
Department of Natural Resources, International Institute for Geo-information Science and Earth
Observation (ITC), Hengelosestraat 99, P.O. Box 6, 7500AA Enschede, The Netherlands; 2
Resource
Ecology Group, Wageningen University, Droevendaalsesteeg 3a, 6708 PB Wageningen, The Netherlands;
3
Logistics and Quantitative Methods, Council for Scientific and Industrial Research, CSIR Built
Environment, P.O. Box 395, 0001 Pretoria, South Africa; 4
School of Resources and Environmental Science,
Wuhan University, Luoyu Road 129, 430079 Wuhan, People’s Republic of China
Abstract. The global spread of highly pathogenic avian influenza H5N1 in poultry, wild birds and humans, poses a sig-
nificant pandemic threat and a serious public health risk. An efficient surveillance and disease control system relies on
the understanding of the dispersion patterns and spreading mechanisms of the virus. A space-time cluster analysis of
H5N1 outbreaks was used to identify spatio-temporal patterns at a global scale and over an extended period of time.
Potential mechanisms explaining the spread of the H5N1 virus, and the role of wild birds, were analyzed. Between
December 2003 and December 2006, three global epidemic phases of H5N1 influenza were identified. These H5N1
outbreaks showed a clear seasonal pattern, with a high density of outbreaks in winter and early spring (i.e., October
to March). In phase I and II only the East Asia Australian flyway was affected. During phase III, the H5N1 viruses
started to appear in four other flyways: the Central Asian flyway, the Black Sea Mediterranean flyway, the East Atlantic
flyway and the East Africa West Asian flyway. Six disease cluster patterns along these flyways were found to be asso-
ciated with the seasonal migration of wild birds. The spread of the H5N1 virus, as demonstrated by the space-time clus-
ters, was associated with the patterns of migration of wild birds. Wild birds may therefore play an important role in
the spread of H5N1 over long distances. Disease clusters were also detected at sites where wild birds are known to
overwinter and at times when migratory birds were present. This leads to the suggestion that wild birds may also be
involved in spreading the H5N1 virus over short distances.
Keywords: H5N1, space-time cluster, migratory waterbirds, wetlands.
Introduction
The highly pathogenic avian influenza H5N1
virus is a highly pathogenic strain of the influenza A
virus, which can cause systemic disease, resulting in
high mortality in bird populations (Swayne and
Halvorson 2003; Swayne and King 2003), and
which can also infect humans and many other ani-
mal species (Cardona et al., 2009). The virus was
detected for the first time in farmed geese in south-
ern China in 1996 (Xu et al., 1999). The first case
of a human becoming infected with the H5N1 virus
was documented in Hong Kong in 1997 (Subbarao
and Katz, 2000). The present outbreak of H5N1
began in December 2003, when South Korea identi-
fied the virus in poultry populations (Lee et al.,
2005). The virus circulated in east and southeast
Asia during 2003 and 2004. In May 2005, the first
H5N1 outbreak in migratory waterfowl was detect-
Corresponding author:
Yali Si
Department of Natural Resources, International Institute for
Geo-information Science and Earth Observation (ITC)
Hengelosestraat 99, P.O. Box 6, 7500AA Enschede
The Netherlands
Tel. +31 53 4874 559; Fax +31 53 4874 338
E-mail: yali@itc.nl
Geospatial Health 4(1), 2009, pp. 65-78
2. Y. Si et al. - Geospatial Health 4(1), 2009, pp. 65-7866
ed at the Qinghai Lake in western China (Chen et
al., 2005, 2006; Liu et al., 2005). In July 2005, the
virus was detected in Russia, and it arrived in
Romania in October 2005 (Gilbert et al., 2006b).
Africa reported its first emergence of H5N1 in
Nigeria in February 2006 (Ducatez et al., 2006).
This global H5N1 epidemic continues to date and
has raised many questions. It is important to find
out what the dispersion patterns of the virus are.
Subsequently, which mechanisms are responsible for
the observed patterns, and more specifically, do
migratory birds play a role in the global H5N1
transmission?
A number of studies have been undertaken to
answer these questions. The worldwide avian
influenza activity has been summarized (Alexander,
2007; Yee et al., 2009). Descriptive methods have
been used to analyse the spread of H5N1 outbreaks
(Tiensin et al., 2005; Gilbert et al., 2006b).
Phylogenetic analyses of the lineage relationship
were executed on the virus strains isolated in eastern
Asia (Li et al., 2004), South Korea (Lee et al., 2008),
Nigeria (Ducatez et al., 2006) and western Africa
(Ducatez et al., 2007). Local level space-time cluster
analyses of H5N1 outbreaks over short time periods
have been carried out in China (Oyana et al., 2006),
Vietnam (Pfeiffer et al., 2007) and Romania (Ward
et al., 2008). The purpose of these studies was to
identify spatio-temporal patterns of the spread of
the disease and to ascertain possible underlying
mechanisms. A study, covering an extended period
of time on a global scale, has not been undertaken
to date, though this is important if knowledge is to
be gained on the worldwide spread of the H5N1
virus. Previous studies (Kilpatrick et al., 2006;
Gilbert et al., 2008) suggested that the movements
of wild birds and domestic poultry were the sus-
pected agents for spreading the virus. Poultry trans-
portation and the wild bird trade were also suspect-
ed agents. Their role in spreading the H5N1 virus is
relatively easy to track and detect, by analysing
trade data (Kilpatrick et al., 2006). However, to
what extent migratory waterbirds can be regarded
as the cause of the virus spread is still under investi-
gation (Feare and Yasué, 2006; Normile, 2006).
Some studies have questioned the role of wild
birds in spreading the H5N1 virus. Weber and
Stilianakis (2007) indicated that it is implausible for
an infected bird to migrate over long distances, as
migration leads to immunosuppression and is nega-
tively affected by virus infection. Feare and Yasué
(2006) questioned an experiment of asymptomatic
infection of wild birds with H5N1, due to chal-
lenges of sample species identification and capture
methods. Also, even though large numbers of birds
migrate through the East Atlantic flyway and East
Asian Australian flyway, the disease currently only
circulates in Eurasia and Africa, without further
spread to America and Australia. This suggests that
migratory birds may not be responsible for the long-
distance spread of the H5N1 virus.
A number of studies, however, do suggest wild
birds may spread the H5N1 virus. Chen et al.
(2004) indicated that ducks can carry the H5N1
virus asymptomatically. Gilbert et al. (2006b)
detected that the directions in which the disease
spread, were consistent with the major bird migra-
tion routes in the western Palaearctic. Brown et al.
(2008) observed that swans and geese can shed
H5N1 virus before and after the onset of clinical
signs, on the basis of an experimental infection of
H5N1 virus. Keawcharoen et al. (2008) found that
some wild duck species showed abundant virus
excretion without clinical or pathologic evidence of
debilitating disease, and therefore could potentially
be long-distance vectors of H5N1.
If H5N1 is spread by wild birds, either over long
or over short distances, this might be deduced from
spatial-temporal patterns of the disease outbreaks
(Onozuka and Hagihara, 2008; Ward et al., 2008).
Wild birds utilize large number of over-staging sites
along the flyways to forage during the migration,
and settle in breeding and wintering sites during the
non-migration seasons. This behaviour determines a
potential role of wild birds in H5N1 spread over
long and short distances, which requires both
regional and local disease patterns to be generated.
Due to intercontinental bird migration and the
3. Y. Si et al. - Geospatial Health 4(1), 2009, pp. 65-78 67
international trade of fowl, the role of wild birds as
disease vectors should be viewed on a global scale
(Kilpatrick et al., 2006). This study was designed to
throw light on the role of wild birds in spreading
H5N1 viruses. The objectives of this study were to
identify the spatio-temporal patterns and dynamics
of H5N1 outbreaks on a global scale, and to further
deduce the role of wild birds in the worldwide
transmission of H5N1 over long and short dis-
tances.
Materials and methods
The main reservoirs of avian influenza are consid-
ered to be waterbirds, such as duck, geese, swan,
gulls, terns and shorebirds (Webster et al., 1992;
Alexander, 2000; Suarez, 2000; Olsen et al., 2006).
Therefore, the possible role of migratory birds in
spreading the H5N1 virus was examined by com-
paring the spatio-temporal dynamics of the disease
clusters with the timing, location and direction of
the major waterbird migration flyways. A flyway is
the entire range a migratory bird species (or groups
of related species or distinct populations of a single
species), uses when moving on an annual basis from
their breeding grounds to non-breeding areas and
back, including intermediate resting and feeding
places (Boere and Stroud, 2006). Figure 1 depicts
the eight broadly grouped flyways of waterbirds,
adapted from information collected and analyzed by
the International Wader Study Group (Asia-Pacific
Migratory Waterbird Conservation Committee,
2001; Stroud et al., 2004). In each flyway, the spring
migration passes in a northward direction and the
autumn migration passes in a southward direction.
The migratory direction is defined based on the
eight waterbird flyways, omitting the complexity of
the migration strategies and systems of individual
waterbird species (Boere and Stroud, 2006). Such
attempts to simplify the main migration routes may
lose information, for example, an important com-
ponent of east-west migration in Eurasia is exclud-
Fig. 1. Eight broad flyways of migratory waterbirds (source: International Wader Study Group).
4. Y. Si et al. - Geospatial Health 4(1), 2009, pp. 65-7868
ed in the above flyways (Scott and Rose, 1996;
Boere and Stroud, 2006). These limitations are con-
sidered when interpreting the results. On the other
hand, strong relationships between the spread of
avian influenza and the major bird migratory routes
would suggest a role.
Data
The time-location series of H5N1 outbreaks were
extracted from official reports provided by the
World Organization for Animal Health (OIE)
(http://www.oie.int). Each report contained the fol-
lowing attributes: province, district, sub-district,
type of epidemiological unit, location, latitude, lon-
gitude, start time, end time, affected species, as well
as the number of susceptible cases, deaths, destroyed
and slaughtered animals. However, from December
2003 to December 2005, most Southeast Asian
reports (mainly in Thailand and Vietnam) lacked lat-
itude and longitude. In this study, the locations of
these outbreaks were geocoded on the basis of the
information provided in the reports, using the centre
of the specific administrative region involved. The
average area of the largest administrative division
(province) in Thailand and Vietnam is 6,716 km2,
equal to an area with a radius of approximately 46
km. Hence, some of the clusters detected (radius
<46 km) in Southeast Asia during this stage, may
suffer from a bias in geocoding, as the original loca-
tion of the outbreaks may have been located some-
where else (maximum 46 km error) than the cen-
troid of the administration division.
Three years of H5N1 outbreak data were used,
from December 2003 to December 2006. Both
Australian and American continents were omitted
from the map because of no report of highly patho-
genic avian influenza H5N1 outbreaks to date (Pei
et al., 2009; Yee et al., 2009). Figure 2a shows the
locations of the outbreaks. The outbreaks were all
concentrated in south and southeast Asia during
2003 and 2004. In 2005, outbreaks continued to be
reported in Asia, but also started to occur in west-
ern Russia and Europe. In 2006, the disease became
pandemic around the Black Sea region, the
Mediterranean region, western Europe and eastern
Africa. Figure 2b shows the locations of two differ-
ent types of outbreaks (i.e., in wild birds and in
poultry). Wild bird outbreaks were concentrated in
western Europe, with sporadic outbreaks being
observed in southern Europe and central Asia.
Poultry outbreaks, however, were concentrated in
southeast Asia (together with wild bird outbreaks
and a few mixed outbreaks), western Russia, the
Black Sea region, Arabia and Africa. As Figure 2 is
displayed for visualization, some specific outbreaks
could be invisible because of overlap with other out-
breaks, such as the wild bird H5N1 outbreak occur-
rence in Egypt in February 2006.
Epidemic curves
To display the outbreaks’ magnitude and trend
over time, epidemic curves were constructed by
counting weekly numbers of outbreaks from 2003
to 2006 in Asia, Europe and Africa. Because the
incubation period (i.e., the length of time between
exposure and onset of symptoms) for avian influen-
za is about 21 days (OIE, 2005), the time unit on the
x-axis was defined as 7 days, equalling one-third of
the incubation period (CDC, 2008). The incubation
period can be shorter, depending on the species and
exposure conditions (WHO, 2006).
Space-time permutation model
The space-time permutation model in scan statis-
tics has been used to test for spatio-temporal clus-
ters, and to identify their approximate location and
timing (Kulldorff et al., 2005). Space-time clusters
occur when an excess number of H5N1 outbreaks
are observed, within a user defined spatial and tem-
poral range. Disease spread is strongly influenced by
the spatial and temporal behaviour of the popula-
tion at risk. The H5N1 outbreaks are of concern to
multiple populations (i.e., poultry, wild bird and
human), which do not always have a clearly defined
distribution, like wild birds. The advantage of the
5. Y. Si et al. - Geospatial Health 4(1), 2009, pp. 65-78 69
space-time permutation model is, that it only
requires actual H5N1 outbreak data (Kulldorff et
al., 2005). The space-time permutation model does
require the population at risk to be constant, so
short analysis periods were selected in order to
respect this requirement (Kulldorff, 2006). The dis-
ease patterns of the different epidemic phases, were
therefore, analysed separately, using the space-time
permutation model and SaTScan software
(http://www.satscan.org). The populations involved
(i.e., the number of bird flocks, farms and villages)
could then be assumed to be constant for each epi-
demic phase.
The space-time permutation model analyzes clus-
ters of H5N1 outbreaks both spatially and temporal-
ly, by testing whether outbreaks that are close in
space are also close in time (Kulldorff, 2006). In the
permutation model, the scanning window forms a
cylinder with the base representing space and the
height representing time. The cylinder begins as a sin-
gle point, gradually increasing both in diameter and
in height, from zero to some maximum value, defined
by the user. The expected number of outbreaks was
calculated on the basis of the null hypothesis, assum-
ing complete spatial randomness, which is synony-
mous with assuming that the observed outbreaks
were approximately independent Poisson random
variables with a constant mean (Diggle, 2003). Based
on this approximation, a likelihood ratio was meas-
ured to determine whether the cylinder contained a
cluster or not. Of all the cylinders evaluated, the one
with the maximum likelihood is considered to be the
primary candidate for a true cluster (Kulldorff et al.,
2005). Statistical significance of detected clusters was
evaluated using a Monte Carlo simulation (Dwass,
1957). The test P-value was estimated by comparing
the rank of the maximum likelihood from the real
data set, with the maximum likelihood from the ran-
dom data sets, defined as P = rank / (1+number of
simulations) (Dwass, 1957; Kulldorff, 2006). A
detailed description and application of space-time
permutation scan statistics can be found in other pub-
lications (Kulldorff et al., 2005; Pearl et al., 2006;
Cooper et al., 2008).
Fig. 2. Worldwide distribution of H5N1 outbreaks from December 2003 to December 2006, displayed by year (a) and by type
of population (poultry or wild birds) (b).
6. Y. Si et al. - Geospatial Health 4(1), 2009, pp. 65-7870
Input parameters
The maximum spatial scanning window should
not exceed 50% of all outbreaks, because otherwise
an extremely low outbreak rate outside the scan-
ning window may not be detected by the algorithm
(Kulldorff, 2006). Two maximum spatial scanning
windows were chosen for this analysis. One for
detecting local clusters, with a 10 km radius, simi-
lar to the surveillance area adopted in the European
Union (Pittman and Laddomada, 2008) and Asian
(Buranathai et al., 2007) surveillance procedures
(i.e., using a 10 km radius zone around infected
premises or flocks). Secondly, a window was chosen
with a radius equivalent to an area covering 10%
of all outbreaks for detecting regional clusters
(Norstrom et al., 2000). Even though poultry
movement was supposedly strictly controlled to
remain within the surveillance areas, the virus
could have been transmitted outside the surveil-
lance zones by wild birds. Given the size and shape
of the study area, the maximum spatial window
covering 10% of total outbreaks was selected to
avoid scanning outside the study area (Sauders et
al., 2003).
The temporal window was also set to be less than
50% of the study period (Kulldorff, 2006). The
maximum temporal scanning window was deter-
mined by a temporal risk window, which is defined
as the period that an infected cluster remains infec-
tious and the virus could be spread to other clusters.
In this study, the maximum temporal scanning win-
dow (temporal risk window) was assumed to be 30
days, starting one day after a initially defined first
lesion date and ending 21 days (the incubation peri-
od) after a slaughter and disinfection period
(assumed to be 9 days).
Other options in the SaTScan software were
selected as follows: (i) retrospective analysis was
selected to allow both “alive” and “historic” clus-
ters to be detected; (ii) scan for high rates was select-
ed for cluster detection; (iii) time aggregation was
not applied, as the maximum temporal scanning
window was set at 30 days and the disease did not
vary considerably over time; (iv) the number of
Monte Carlo simulations was set at 999; and (v) the
most likely clusters and non-overlapping secondary
clusters were selected. For mapping purposes, sig-
nificant clusters (P <0.05) were classified into five
risk levels, according to the relative risk obtained
from the analysis result.
Role of wild birds in H5N1 spread
To deduce the role of wild birds in H5N1 spread
over long distance, bird migration patterns were
compared with the disease trajectory. All regional
and local clusters indentified along flyways that
follow the migration routes were considered
potentially related to wild birds. To deduce the
role of wild birds in H5N1 spread over short dis-
tance, we examined whether the local clusters
were found at sites where wild birds are known to
overwinter and at times when migratory birds
were present.
Results
Epidemic curves
Visual inspection of the epidemic curves (Fig. 3)
indicated three epidemic phases at the global level,
i.e. phase I extending from week 50 (2003) to week
15 (2004), phase II from week 21 (2004) to week 16
(2005), and phase III from week 23 (2005) to week
51 (2006). Asia was involved in all disease outbreak
phases, with peaks observed in week 4 (2004) dur-
ing phase I, in week 41 (2004) during phase II and
in week 46 (2005) during phase III. European and
African outbreaks were only reported in phase III.
The epidemic in Europe lasted from week 37 (2005)
to week 26 (2006), with three peaks in weeks 2, 8
and 20 (2006). The epidemic in Africa overlapped
with the European epidemic and lasted from week 2
to week 23 (2006), with a peak in week 12. All three
epidemic phases revealed a high occurrence of
H5N1 outbreaks in winter and early spring (i.e.,
from October to March).
7. Y. Si et al. - Geospatial Health 4(1), 2009, pp. 65-78 71
Dynamics of space-time H5N1 clusters and corre-
lated flyways
A total of 143 space-time clusters (P <0.05) were
identified by the space-time permutation scan statis-
tic, with 20, 20 and 74 local clusters, and another 8,
12 and 9 regional clusters forming for the three
phases, respectively. The temporal dynamics of the
identified space-time clusters in the three global epi-
demic phases were displayed in Figure 4, and over-
laid with the five correlated flyways. (i.e., the East
Asia Australian, the Central Asian, the Black Sea
Mediterranean, the East Atlantic and the East Africa
West Asian flyway).
Global H5N1 epidemic phase I
During the first stage of the disease outbreak, in
December 2003 (Fig. 4Ia), significant clusters were
identified in Indonesia, Korea and Vietnam, with
low risk of infection in Southeast Asia and high risk
in Korea. In January 2004 (Fig. 4Ib), the virus cir-
culated throughout Vietnam at both local and
regional level, forming six low risk clusters.
Meanwhile, another low risk regional cluster
occurred in southeast China. In February 2004 (Fig.
4Ic), one local cluster was identified in Indonesia,
followed by one regional cluster in Thailand. Then,
medium and high risk clusters started appearing in
Cambodia and Japan. In April 2004 (Fig. 4Id),
another high risk local cluster was identified in
Thailand. During this phase, only one major migrat-
ing bird flyway (the East Asia Australian flyway)
was affected.
Global H5N1 epidemic phase II
From March to May 2004 the H5N1 virus showed
little activity, but then low and medium risk clusters
started appearing in Thailand between June and
December 2004 (Fig. 4IIa-g). Medium risk clusters
were also identified in Malaysia in September (Fig.
4IId) and in Indonesia in December of that same year
(Fig. 4IIg). In January and February 2005 (Fig. 4IIh-
i), ten disease clusters were located in Vietnam, at
both local and regional level, with low and medium
risk factors. The disease reoccurred in Thailand in
February (Fig. 4IIi), and in Indonesia in February and
March 2005 (Fig. 4IIi-j), forming one and six clusters,
respectively. As during the first phase, the H5N1 virus
was limited to the East Asia Australian flyway.
Fig. 3. Epidemic curves of reported H5N1 outbreaks from
December 2003 to December 2006, displayed respectively for
Asia, Europe and Africa. The three epidemic phases are sepa-
rated by dashed lines.
8. Fig. 4. Monthly dynamics of significant space-time clusters (P <0.05) in each epidemic phase. The size of the circle is deter-
mined by the value of the relative risk (ratio of observed to expected outbreaks) and overlaid with the correlated flyways. Black
circles indicate local clusters (radius δ 10 km) and red circles indicate regional clusters (radius >10 km).
Y. Si et al. - Geospatial Health 4(1), 2009, pp. 65-7872
Global H5N1 epidemic phase III
As in 2004, no H5N1 clusters were identified dur-
ing April, May or June 2005. In July and August
2005 (Fig. 4IIIa-b), eight clusters were located in
western Russia and Kazakhstan. In southeast Asia,
clusters were identified in Thailand between July
and September (Fig. 4IIIa-c), reappearing in south
9. Y. Si et al. - Geospatial Health 4(1), 2009, pp. 65-78 73
Indonesia during October (Fig. 4IIId). Eighteen clus-
ters were identified in Vietnam between October
and December 2005, forming either a low or a
medium risk, at both local and regional level (Fig.
4IIIe-f). In October 2005, another medium risk clus-
ter was located in western Russia (Fig. 4IIId).
Thereafter, some sporadic outbreaks were reported
in the Black Sea region, leading to four clusters (two
of them high risk) in Ukraine and two medium risk
clusters in Romania in December 2005 (Fig. 4IIIf).
Disease clusters were also identified in the eastern
Mediterranean in January 2006 (two of them low
risk and five medium risk clusters) and in Nigeria,
where three local clusters occurred in January and
February 2006 (Fig. 4IIIg-h).
In February 2006 (Fig. 4IIIh), more disease clus-
ters were located in the eastern Mediterranean
region, forming one high risk local cluster in Italy
and four low and medium risk clusters (at both
local and regional level) in Egypt. Within the same
month, two local clusters were identified in
Slovenia and France, with a high and low risk fac-
tor, respectively (Fig. 4IIIh). By March 2006 there
were outbreaks in northern Europe (Fig. 4IIIi),
with two local clusters (medium to high risk) and
one low risk regional cluster in Denmark. Another
six clusters (low to medium risk) appeared in
Egypt during March (Fig. 4IIIi). In April 2006 (Fig.
4IIIj), two medium risk local clusters were located
in Sudan, as well as one medium risk local cluster
in Pakistan. Meanwhile in Asia, one local cluster
was identified in Hong Kong in February 2006
(Fig. 4IIIh), and three clusters (at both local and
regional level) in Myanmar in March and April
(Fig. 4IIIi-j). The disease appeared in Romania
(five low to medium risk clusters) in May (Fig.
4IIIk), and in neighbouring Hungary (one medium
risk cluster) in June 2006 (Fig. 4IIIl). After a rela-
tively long period with low virus activity (July to
October 2006), one final high risk local cluster
was identified in Korea in November 2006 (Fig.
4IIIm).
During this third epidemic phase, the H5N1 virus
circulated chronologically, via the East Asia Atlantic
flyway to the Central Asian flyway, the Black Sea
Mediterranean flyway, the East Atlantic flyway and
finally the East Africa West Asian flyway.
Space-time H5N1 clusters along and across flyways
Based on the five identified flyways (Fig. 4), the
sum of clusters occurring per month within each fly-
way was plotted. A chronology emerges, indicating
the spread of disease clusters along and across fly-
ways, as shown in Figure 5.
Disease clusters appeared throughout the East Asia
Australian flyway during the whole study period,
with peaks in December 2003, February and
November 2005. In the Central Asian flyway, disease
clusters started emerging in July 2005 and waned in
October 2005. In the Black Sea Mediterranean fly-
way, clusters lasted from December 2005 to March
2006. Finally, clusters appeared in the East Atlantic
and East Africa West Asian flyways in March and
April 2006, respectively.
Dynamics of space-time H5N1 clusters and season-
al bird migration
Six H5N1 cluster patterns were found to be asso-
ciated with the seasonal migration of waterbirds
(Fig. 6). In February 2004, a northbound spread of
disease clusters was identified from Indonesia, via
Thailand and Cambodia, to Japan. This disease pat-
tern coincided with the wild bird spring migration
northwards via the East Asia Australian flyway (Fig.
6a). During the autumn migration (August to
November in 2004), the birds migrated southwards
via the East Asia Australian flyway, which coincid-
ed with the disease spreading into Southeast Asia
(Fig. 6b), as space-time clusters shifted from
Thailand (August), via Malaysia (September), to
south Indonesia (December). In the autumn of 2005
(Fig. 6c), a similar pattern was detected, in Thailand
(September) and Indonesia (October), the disease
clusters again following a north-south direction,
overlapping with the birds’ migration route via the
East Asia Australian flyway.
10. Y. Si et al. - Geospatial Health 4(1), 2009, pp. 65-7874
The disease clusters detected in western Russia
(October 2005), the Black Sea region (December
2005) and Nigeria (January 2006), occurred in a
northeast to southwest direction and coincided with
peak migratory movements via the Black Sea
Mediterranean flyway during autumn (Fig. 6d).
During spring 2006 (Fig. 6e), space-time clusters
were detected from Italy, Slovenia and neighbouring
countries (February), to Denmark (March), as well
as from Nigeria (February) to Denmark (March),
following south-north directions. The spatio-tempo-
ral dynamics of these disease clusters correspond
with the timing and direction of bird migration
along both the Black Sea Mediterranean flyway and
the East Atlantic flyway. In April 2006, disease clus-
ters were first observed in Sudan, and then in
Pakistan (Fig. 6f), which coincide with the direction
and timing of birds migrating over the East Africa
West Asian flyway.
Discussion
The H5N1 virus outbreaks can be divided into
three global epidemic phases. By displaying the
monthly dynamics of the space-time clusters of the
disease and the matching migratory flyways of wild
birds, a quantitative description is presented of
H5N1 transmission at a global scale, and the possi-
ble relationship between migratory birds and the
spread of the disease is revealed. The H5N1 out-
breaks were mainly concentrated in winter and early
spring (from October to March), suggesting a sea-
sonally higher risk of infection.
The possibility of long-distance virus spread by
migratory birds
A chronology of H5N1 infections developed from
the East Asia Atlantic flyway to the Central Asian
flyway, the Black Sea Mediterranean flyway, the
East Atlantic flyway and finally the East Africa West
Asian flyway, suggesting that the H5N1 virus may
be transmitted by wild birds via the different fly-
ways. Possible reasons are that migratory birds may
become infected when sharing breeding grounds in
Siberia, as well as overlapping flyways creating
opportunities for birds to come into contact with
each other.
The correlation between disease cluster patterns
and seasonal wild bird migration suggests that wild
birds may spread the virus over long distances.
Some of our results are consistent with a previous
report (Gilbert et al., 2006b), indicating that
Anatidae may spread the virus from Russia and
Kazakhstan to the Black Sea region during the
autumn migration. We found that the virus also
appeared in Nigeria after the Black Sea region had
been infected. The pandemic in Nigeria occurred in
January 2006, after the migratory season, but the
virus may have already been present in the popula-
tion of birds overwintering in Nigeria, with out-
breaks not occurring until some time after the
arrival of the migratory birds. A similar delay was
observed in Romania, where the virus was first
detected in October 2005, but the first high risk
cluster was not detected till December 2005.
Ducatez et al. (2006) found that the three H5N1
lineages found at two farms in Nigeria were inde-
pendently introduced through routes coinciding
with the migratory bird flyway. Our findings also
support a previous study which suggest that the
African sublineages emerged outside of Africa but
Fig. 5. Space-time H5N1 clusters along and across the flyways.
11. Y. Si et al. - Geospatial Health 4(1), 2009, pp. 65-78 75
followed the East African West Asian and Black Sea
Mediterranean flyways, as at least two of the sub-
lineages isolated in western Africa also circulated in
Germany during 2006 (Ducatez et al., 2007).
However, human mobility can not be excluded com-
pletely, as Nigeria imports large numbers of poultry,
without rigorous bio-security safeguards, from dif-
ferent countries in the world (Ducatez et al., 2006).
The long-distance disease spread does coincide with
the seasonal pattern of bird migration over the
Black Sea Mediterranean flyway.
All this evidence supports the hypothesis, that the
spread of the H5N1 virus is associated with migra-
tory movements of birds via well-known flyways.
Though our study attempts to seek the role of wild
birds in spreading H5N1 virus by correlative stud-
ies, this of course does not constitute “proof”. In
other words, human mobility cannot be ruled out as
a vector in the observed patterns of virus transmis-
sion. Besides, some spatio-temporal patterns of the
disease clusters, such as in Egypt (February 2006)
and Sudan (March 2006), do not follow the domi-
nant flyway direction from South to North trend
expected for that time of the year, which may be
caused by poultry transportation with H5N1 virus.
Latitudinal and unusual bird movements may facil-
itate the H5N1 virus spread as well. Gilbert et al.
(2006b) suggested that the western European pan-
demic was caused by unusual waterfowl movements,
due to unseasonably cold weather in the Black Sea
area, where the virus was already established.
However, detailed and localized bird movement pat-
terns are required to further test this hypothesis,
which is beyond the scope of the current study.
The possibility of short-distance virus spread by
migratory birds
Migratory birds could be involved in short-dis-
tance virus spreading, especially where disease clus-
ters were detected in overwintering areas. A large
number of disease clusters was detected during win-
ter and spring in important staging and overwinter-
ing regions for migratory waterbirds (http://ram-
sar.wetlands.org/Default.aspx), such as Xuan Thuy
Natural Wetland Reserve in Vietnam, Chany Lakes
in Russia, Kizilirmak Delta in Turkey, Aquatic-cliff
complex of Karadag in Ukraine, South Funen
Archipelago in Denmark, Vendicari in Italy and
Maldunba Lake in Nigeria. By sharing staging and
overwintering sites, migratory waterbirds come into
contact with other flocks of birds, as well as with
free-ranging poultry (Gilbert et al., 2006a; Onozuka
and Hagihara, 2008), facilitating the spread of dis-
ease. In addition, the outbreaks in western Europe
and central Asia (Fig. 2), showed few or no infec-
tions in poultry, suggesting that wild birds have to
play a role in the virus transmission.
Infected migratory birds may facilitate the virus
spread by contaminating overwintering sites, as the
virus may survive without a host for extended peri-
ods, especially at low temperatures. Stallknecht et
al. (1990) determined that water with an initial con-
centration of 1 x 106 TCID50 (50% tissue culture
infective dose) could remain infectious for up to 207
days at 17°C or up to 102 days at 28°C. As the
H5N1 virus remains virulent in bird faeces for at
least 35 days at 4°C and 6 days at 37°C (OIE,
2008), the frequent reoccurrences of disease clusters
in Thailand (June to December 2004, July to
September 2005), west Russia (July, August and
October 2005), Vietnam (October to December
2005) and the Black Sea region (May and June
2006), suggest that local outbreaks may be caused
by viruses surviving in contaminated areas.
Both local and regional clusters were assumed to
be associated with epidemic risks in this study.
However, we cannot exclude the possibility of some
clusters, especially local ones, having no relation-
ship with bird migration. Distinguishing epidemic
risk clusters from endemic risk clusters requires
extra data, such as distribution pattern of genetic
lineage. This study explored the maximally possible
role of wild bird in spreading H5N1 virus at either
regional or local scales. We recommend confirming
these findings by using genetic lineage distribution
patterns to exclude endemic risks in future studies.
In conclusion, the spread of the H5N1 virus, as
12. Y. Si et al. - Geospatial Health 4(1), 2009, pp. 65-7876
quantified by the space-time clusters, was found to
be associated with the timing, location and direction
of continental bird migration, suggesting that wild
birds spread H5N1 over long distances. Disease
clusters were also detected at sites that are known
overwintering areas, and at times when these areas
were frequented by migratory birds, suggesting that
wild birds are involved in short distance H5N1
spread as well.
Acknowledgements
This research is sponsored by the China Scholarship
Council (CSC) and the International Institute for Geo-
Information Science and Earth Observation (ITC).
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