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Against culling


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Against culling

  1. 1. Using biodiversity in husbandry practices for disease controlCheryl LansNovember 24, 2006Culling (stamping out) for the control of contagious diseases is one of theearliest methods used by the veterinary profession and originated inBritain in 1892.For trade-related reasons culling has been preferred to vaccination which may masksymptoms or produce carrier animals. Therefore vaccination does not necessarily stopcontamination of the environment with the infectious agent; however it can reduce thespread of the infectious agent. 1
  2. 2. Culling has been criticized for the following reasons: 1. for the emotional impact it has on the owners, on meat consumers and rural populations, 2. for being indiscriminate – healthy, valuable and disease-resistant animals in affected areas are also killed, 3. it is hugely expensive [but not necessarily more expensive than vaccination in a capitalism-friendly political environment]. 4. it can contribute to the spread of the target disease. 5. it has a negative impact on biodiversity (including the genetic breeds favoured by small scale and organic farmers, and wild species that may be affected in future epidemics). 6. biodiversity is also affected when local people turn to “bushmeat” to replace their culled poultry in their diets. 2
  3. 3. Underlying assumptions of culling  The most basic assumption behind stamping out is that a disease-free existence is optimal and can be achieved.  A second related assumption is that given enough resources a disease can be eradicated and this will be more cost effective than having lost productivity from sub-clinical and clinical infections, medication costs and lost opportunities for international trade. However “enough resources” rarely exists in practice and very few diseases have actually been eradicated. For example the SARS outbreak (in 30 countries and with approximately 8500 deaths) cost between US$10 billion to US$30 billion (Robertson, 2002). It is unlikely that these resources can be continuously spent on each new serious outbreak without a long term economic impact  3
  4. 4. A third assumption is that eradicating a disease justifies any resulting loss in biodiversity. This assumption may be linked to the fourth assumption. The fourth assumption is that scientists can genetically-engineer more productive species than those that originally existed. The most important assumption is that cheap food and cheap protein are universal goods that should be achieved whatever the environmental costs. First there is already sufficient food, but it is poorly distributed and post- harvest losses and wastage are immense. Given the current obesity pandemic and the linked increase in famine and desertification it is obvious that there are environmental limits to the provision of cheap food that have not been overcome. The cost effectiveness of living within environmental limits? 4
  5. 5. Avian flu 1. Millions of economic resources have gone into vaccination, outreach and research programs, in order to prevent new pandemics. While it is encouraging to see an increase in scientific jobs, these resources must have been diverted from other uses. 2. Millions of birds have been killed. These birds have more genetic diversity than the industrial poultry being protected. 3. Organic practices are being curtailed (animals have to be kept indoors) although there is no scientific evidence that organic practices increase the spread of the disease. However there is mounting scientific evidence that animal welfare increase in organic systems. 4. Exotic diseases can be dealt with on a case-by-case basis and these regional or country specific diseases do not normally cause great perturbations. 5. Medicinal plants exist that could be used for disease control (Lans et al., 2006).The following plants, usually immersed in the drinking water, are used to control clinicalsigns of unspecified respiratory disease in poultry globally:Three of these species (Allium sativum, Andrographis paniculata and Nicotiana glauca)and species of three other genera (Citrus, Euphorbia and Mahonia) have anti-influenzaactivity. A further seven species (Curcuma longa, Eryobotrya japonica, Momordicacharantia, Ocimum sanctum, Plantago major, Ricinus communis and Zingiber officinale)demonstrate activity against other viruses. Momordica charantia 5
  6. 6. Computer simulationsMost computer simulations model the spread of the disease in a target population as itis. For example scientists working with the Models of Infectious Disease Agent Study(Midas) research network have concluded that immediate treatment with vaccines andantiviral drugs as well as quarantines and other standard public health measures wouldprevent a pandemic.Simulations could be used to change the underlying assumptions of livestock husbandry.For example industrial agriculture and globalized trade are considered to be bestpractice and most efficient. It should be possible to model organic agriculture and localfood provision as best practice based on the increased hardiness of livestock raisedorganically and the reduced food miles of local food.Rather than model the target population as it currently is, the simulations will changethe practice of animal husbandry in the target population to organic (including the useof medicinal plants), and reduce the level of international food-related trade and theninvestigate whether these modifications have any effect on the spread of disease. 6
  7. 7. Example of a Methodological Approach 1. Map the spread of avian flu against industrial food trade routes to see if there is any correlation. 2. Document the location of the ~ 100 people who have died of avian flu – whether they were close to industrial operations or trade routes or whether they were involved in backyard operations. 3. Document through literature study the symptoms of the people who died and those who recovered and if possible what they were treated with. 4. Compare the costs of disease control in the past when it was largely tax-payer funded to the current privatized provision (pharmaceutical companies recovering their research costs). 7
  8. 8. Researchers in the United Kingdom postulate that humancommerce routes, rather than bird migratory routes,are responsible for the spread of avian influenza.Source: Eilat-Guide 5. Create computer models of alternative husbandry strategies and trade practices and examine their impact on disease spread: o Simulation 1: This simulation will investigate what would happen if all the industrial food production including slaughter plants was compartmentalized close to airports and ports. The costs and benefits of this approach will be examined in 3 representative countries (Europe, Asia, Americas) o Simulation 2: This simulation will investigate what the economic impact of requiring all industrial food producers not in compartmentalized areas to adopt organic or modified organic principles. The impact if any this would make on new disease emergence and spread will then be investigated. o Simulation 3: This simulation will assess the potential economic impact of a restricting all food production to small or medium scale, localized and fully in compliance with the principles of ecosystem health and use of biodiversity. This simulation will estimate the costs and benefits of this approach. 8
  9. 9. ReferencesBano S, Naeem K, Malik SA. 2003. Evaluation of pathogenic potential of avian influenza virus serotype H9N2 in chickens. Avian Dis. 2003; 47(3 Suppl):817-22.Bennun, Leon. 2006. Reality takes wing over bird flu. BBC News February 17, 2006. I, Terregino C, Cattoli G, Toffan A. 2004. Increased resistance of vaccinated turkeys to experimental infection with an H7N3 low-pathogenicity avian influenza virus. Avian Pathol. 2004;33(2):158-163.GRAIN, 2006. Fowl play: The poultry industrys central role in the bird flu crisis. Robertson, 2002. The Economic Costs of Infectious Diseases. Research Note no. 36 2002-03, Foreign Affairs, Defence and Trade Group. 13 May 2003, Parliament of Australia.Lans, C., Khan, T., Martin-Curran M., McCorkle, C.M. Ethnoveterinary Medicine: Potential solutions for large-scale problems. Book chapter submitted for publication in a Mosby textbook entitled "Veterinary Herbal Medicine" edited by Susan Wynn, DVM and to be published in 2006Simon J. Barteling and Paul Sutmoller, 2002. Culling versus vaccination: challenging a dogma in veterinary (FMD) science. Report of the Session of the Research Group of the Standing Technical Committee of EUFMD. Appendix 15. EUFMD Research Group Meeting 2002 - Çesme, Izmir g%202001%20-%20Maisons%20Alfort.htmSwayne DE, Beck JR. 2005. Experimental study to determine if low-pathogenicity and high-pathogenicity avian influenza viruses can be present in chicken breast and thigh meat following intranasal virus inoculation. Avian Dis.49(1):81-5.Walbridge, Rob. 2006. Terrorist ducks and free-range sleeper cells., Dawn. 2006. Scientists hand Ottawa a blueprint for a mass cull of bison. Globe and Mail March 21, 2006. 9