3. Introduction
In the early 1970s, it was widely
assumed that infectious diseases
would continue to decline
3
4. Introduction cont…
Worldwide, at least 30 new and re-emerging
infectious diseases have been recognized since
1975.
HIV/AIDS has become a serious pandemic.
Several ‘old’ infectious diseases, including
tuberculosis, malaria, cholera and dengue fever,
have proven unexpectedly problematic.
4
5. Introduction cont…
Reasons for the increased occurrence of these
(old) diseases include:
increased antimicrobial resistance
new ecological niches
weak public health services
activation of infectious agents
5
6. Introduction cont…
Diarrheal disease, acute respiratory
infections and other infections continue to
kill more than seven million infants and
children annually
Mortality rates among children are
increasing in parts of sub-Saharan Africa
6
7. Introduction cont…
Success: Availability of antimicrobial agents &
vaccines in the 1950s through the 1970s led to
reduction in disease occurrence
Challenge -unexpected emergence of new
infectious diseases and the re-emergence of
previously controlled diseases that became
apparent in the 1980s and 1990s
7
8. Introduction cont…
Intentional release of infectious agents in a
deliberate effort to frighten, harm, or kill
(Bioterrorism) has become also a concern
Bioterrorism - deliberate release of viruses,
bacteria, or other germs (agents) used to
cause illness or death in people, animals, or
plants.
8
9. Introduction cont…
These agents are typically found in
nature
but it is possible that they could be
changed to:
– increase their ability to cause
disease,
– make them resistant to current
medicines, or
– increase their ability to be spread
into the environment
9
10. Introduction cont…
Anthrax is example of biological agent that
could be used for bioterrorism.
A biological attack may not be recognized
immediately and may take local health care
workers time to discover that a disease is
spreading in a particular area.
10
11. Emerging & reemerging infectious diseases include:
Diseases caused by microbial agents not previously
known to cause illness in humans (e.g ,COVID-19,
SARS, avian influenza in humans, swine flu)
The appearance in a new location of an infectious agent
(e.g the spread of West Nile virus to the US)
The appearance of a new epidemiologic pattern of
disease caused by an infectious agent (e.g epidemic
meningococcal meningitis caused by serogroup W-135
N.meningitidis)
Introduction cont…
11
12. The appearance or spread of new variants of
an infectious agent (e.g multidrug resistant
M.tuberculosis)
The resurgence of an infectious disease
previously under good control (e.g diphtheria
in parts of the former Sovient Union)
Introduction cont…
12
13. Some diseases result in dramatic outbreaks that
command widespread public attention &
political response (e.g SARS & avian influenza),
Other equally serious infectious disease threats
(e.g multidrug-resistant tuberculosis) often go
largely unnoticed by the general public &
decision makers because they do not produce
explosive epidemics
Introduction cont…
13
14. Factors that could promote the emergence
or reemergence of infectious disease threats
Agent-related factors
Evolution of pathogenic infectious agents
(microbial adaptation and change)
Development of resistance to drugs
Resistance of vectors to pesticides.
14
15. Host-related factors
Human demographic changes (humans
inhabiting new areas)
Human behavior (sexual practices and drug
use)
Human susceptibility to infection
(immunosuppression)
Poverty and social inequality. 15
16. Environment related factors
Climate and changes in the ecosystem.
Economic development and land use
(urbanization, deforestation).
Technology and industry
International travel and commerce
Breakdown of public health interest in certain
situations (war, unrest, overcrowding)
Deterioration of surveillance systems 16
17. Future focus
1. Continue efforts to control existing
infectious diseases
2. improve global capacity for early detection
and rapid response to newly emergent or
re-emergent infectious diseases
17
18. WHO phases of pandemic alert
Current phases of alert in the WHO global
influenza preparedness plan
Pandemic preparedness
In the 2009 revision of the phase
descriptions, WHO has retained the use of
a six-phased approach.
18
20. Pandemic influenza phases
Phases 1–3 correlate with preparedness,
including capacity development and
response planning activities
Phases 4–6 clearly signal the need for
response and mitigation efforts.
20
21. Phase I
No viruses circulating among animals
have been reported to cause infections
in humans.
21
22. Phase 2
Animal influenza virus circulating
among domesticated or wild animals
is known to have caused infection in
humans
therefore it is considered a potential
pandemic threat.
22
23. Phase 3
sporadic cases or small clusters of
disease in people
but has not resulted in human-to-
human transmission sufficient to
sustain community-level outbreaks.
23
24. Phase 3 cont…
Limited human-to-human transmission may
occur under some circumstances
E.g, when there is close contact between an
infected person and an unprotected caregiver.
However, limited transmission under such
restricted circumstances does not indicate that
the virus has gained the level of transmissibility
among humans necessary to cause a pandemic.
24
25. Phase 4
Characterized by verified human-to-human
transmission able to cause “community-
level outbreaks.”
The ability to cause sustained disease
outbreaks in a community marks a
significant upwards shift in the risk for a
pandemic.
25
26. Phase 4 cont….
Any country that suspects or has verified
such an event should urgently consult with
WHO
the situation can be jointly assessed and a
decision made by the affected country if
implementation of a rapid pandemic
containment operation is warranted.
Phase 4 indicates a significant increase in
risk of a pandemic.
26
27. Phase 5
characterized by human-to-human spread of the
virus into at least two countries in one WHO
region.
While most countries will not be affected at this
stage, the declaration of Phase 5 is a strong signal
that a pandemic is imminent and that the time to
finalize the organization, communication, and
implementation of the planned mitigation
measures is short.
27
28. Phase 6 (the pandemic phase)
characterized by community level
outbreaks in at least one other country in a
different WHO region in addition to the
criteria defined in Phase 5.
Designation of this phase will indicate that
a global pandemic is under way.
28
29. Post-peak period
pandemic disease levels in most countries
with adequate surveillance will have
dropped below peak observed levels.
This signifies that pandemic activity appears
to be decreasing;
however, it is uncertain if additional waves
will occur and countries will need to be
prepared for a second wave.
29
30. Post-pandemic period
influenza disease activity will have returned to
levels normally seen for seasonal influenza.
It is expected that the pandemic virus will behave
as a seasonal influenza A virus.
It is important to maintain surveillance and
update pandemic preparedness and response
plans accordingly.
An intensive phase of recovery and evaluation
may be required. 30
32. WHO Regions cont…
• WHO African Region (46 countries)
• WHO European Region (53 countries)
• WHO Eastern Mediterranean Region (21
countries)
• WHO Region of the Americas (35 countries)
• WHO South-East Asia Region (11 countries)
• WHO Western Pacific Region (27 countries)
32
33. Countries in the WHO African
Region
Algeria, Angola, Benin, Botswana, Burkina Faso,
Burundi, Cameroon, Cape Verde, Central African
Republic, Chad, Comoros, Congo, Côte d'Ivoire,
Democratic Republic of the Congo , Equatorial Guinea ,
Eritrea, Ethiopia, Gabon, Gambia, Ghana, Guinea,
Guinea-Bissau, Kenya, Lesotho , Liberia, Madagascar,
Malawi, Mali, Mauritania, Mauritius, Mozambique,
Namibia, Niger , Nigeria, Rwanda, Sao Tome and
Principe, Senegal, Seychelles, Sierra Leone, South
Africa , Swaziland, Togo, Uganda, United Republic of
Tanzania, Zambia, Zimbabwe
33
34. WHO European Region
Albania, Andorra, Armenia, Austria, Azerbaijan, Belarus,
Belgium, Bosnia and Herzegovina, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Georgia, Germany, Greece, Hungary, Iceland,
Ireland, Israel, Italy, Kazakhstan, Kyrgyzstan, Latvia,
Lithuania, Luxembourg, Malta, Monaco, Montenegro,
Netherlands, Norway, Poland, Portugal, Moldova,
Romania, Russian Federation , San Marino, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland ,
Tajikistan, The former Yugoslav Republic of Macedonia
, Turkey, Turkmenistan, Ukraine, United Kingdom ,
Uzbekistan
34
35. Countries in the WHO Eastern
Mediterranean Region
Afghanistan, Bahrain, Djibouti, Egypt, Iran
(Islamic Republic of), Iraq, Jordan,
Kuwait, Lebanon, Libyan Arab Jamahiriya,
Morocco, Oman, Pakistan, Qatar, Saudi
Arabia, Somalia, Sudan, Syrian Arab
Republic, Tunisia, United Arab Emirates,
Yemen
35
36. Countries in the WHO Region
of the Americas
Antigua and Barbuda , Argentina, Bahamas,
Barbados, Belize, Bolivia, Brazil , Canada, Chile,
Colombia, Costa Rica, Cuba, Dominica, Dominican
Republic , Ecuador, El Salvador, Grenada,
Guatemala, Guyana , Haiti, Honduras, Jamaica,
Mexico, Nicaragua, Panama, Paraguay, Peru, Saint
Kitts and Nevis, Saint Lucia, Saint Vincent and the
Grenadines, Suriname, Trinidad and Tobago, United
States of America , Uruguay, Venezuela (Bolivarian
Republic of)
36
37. Countries in WHO South-East Asia
Region
Bangladesh, Bhutan, Democratic People's
Republic of Korea, India, Indonesia,
Maldives, Myanmar, Nepal, Sri Lanka,
Thailand, Timor-Leste
37
38. Countries in the WHO Western
Pacific Region
Australia, Brunei Darussalam, Cambodia,
China, Cook Islands, Fiji, Japan, Kiribati,
Lao People's Democratic Republic,
Malaysia, Marshall Islands, Micronesia
(Federated States of), Mongolia, Nauru,
New Zealand, Niue, Palau, Papua New
Guinea, Philippines, Republic of Korea,
Samoa, Singapore, Solomon Islands,
Tonga, Tuvalu, Vanuatu, Viet Nam
38
39. Severe Acute Respiratory
Syndrome (SARS)
Was one of the most dramatic emerging infectious
disease threat in recent years
This life threatening form of pneumonia appears to have
originated in southern China in late 2002
Before the significance of these cases of pneumonia
became apparent, the illness had spread to multiple other
parts of Asia, Europe, North America, and elsewhere
39
40. SARS cont…
By the middle of 2003, over 8,400 probable cases of
SARS & over 800 SARS related deaths had been
reported from 30 countries, with China, Hong Kong, and
Taiwan bearing the burden of the epidemic
SARS is caused by a previously unknown member of the
Coronaviridiae family that originated in animal
reservoirs
40
41. Mode of transmission of SARS
The virus initially spread to humans with direct
exposure to infected animals (? Bats) in
southern China
However, the virus proven to be transmissible
from person to person, particularly in the health
care settings
The ease of modern travel facilitated the rapid
dissemination of the virus across the globe
41
42. Mode of transmission cont…
The primary way of transmission - close person-to-
person contact.
Can be transmitted most readily by respiratory
droplets produced when an infected person coughs
or sneezes.
Droplet spread can happen when droplets from the
cough or sneeze of an infected person are propelled
a short distance (generally up to 3 feet) through
the air and deposited on the mucous membranes of
the mouth, nose, or eyes of persons who are nearby.
42
43. Mode of transmission cont…
can also spread when a person touches a
surface or object contaminated with infectious
droplets and then touches his/her mouth, nose,
or eye(s).
In addition, it is possible that SARS might be
spread more broadly through the air (airborne
spread) or by other ways that are not now
known
43
44. Mode of transmission cont…
The incubation period for SARS is
typically 2 to 7 days, although in some
cases it may be as long as 10 days.
In a very small proportion of cases,
incubation periods of up to 14 days have
been reported.
44
45. Mode of transmission cont…
Persons with SARS are most likely to be contagious
only when they have symptoms, such as fever or cough.
Patients are most contagious during the second week of
illness.
However, as a precaution against spreading the disease,
CDC recommends that persons with SARS limit their
interactions outside the home until 10 days after their
fever has gone away and their respiratory symptoms
have gotten better.
45
46. Avoiding risk of acquiring the
infection
frequent hand washing with soap and water or
use of an alcohol-based hand rub.
avoid touching your eyes, nose, and mouth with
unclean hands
encourage people around you to cover their nose
and mouth with a tissue when coughing or
sneezing. 46
47. Strategies used to prevent further
spread of SARS
• In the absence of a vaccine, preventing further
spread of the epidemic required:
– stringent isolation of patients,
– quarantine of individuals,
– restrictions on travel, and
– various other measures that were highly
disruptive of commerce, travel, and other
aspects of life 47
48. Bird Flu
Although Avian Influenza A viruses usually
do not infect humans, rare cases of human
infection with Avian Influenza A viruses
have been reported.
Most human infections with avian influenza
A viruses have occurred following direct
contact with infected poultry.
48
49. Bird Flu cont…
Since November 2003, nearly 400 cases of human
infection with highly pathogenic Avian Influenza A
(H5N1) viruses have been reported by countries in
Asia, Africa, the Pacific, Europe and the Near
East.
Most human cases of H5N1 virus infection are
thought to have occurred as a result of direct
contact with sick or dead infected poultry
49
50. Bird Flu cont…
The spread of avian influenza A viruses from one
ill person to another has been reported very
rarely, and has been limited, inefficient and
unsustained.
However, because avian influenza A viruses have
the potential to change and gain the ability to
spread easily between people, monitoring for
human infection and person-to-person
transmission is important.
50
51. Bird Flu cont…
Signs and symptoms of Avian Influenza in
Humans
range from eye infections (conjunctivitis) to
influenza-like illness symptoms (e.g., fever,
cough, sore throat, muscle aches) to severe
respiratory illness (e.g. pneumonia, acute
respiratory distress, viral pneumonia) sometimes
accompanied by nausea, diarrhea, vomiting and
neurologic changes. 51
52. Bird Flu cont…
Antiviral Agents for Avian Influenza A Virus Infections of
Humans
• CDC and WHO recommend oseltamivir for treatment and
prevention of human infection
• Analyses of available H5N1 viruses circulating worldwide
suggest that most viruses are susceptible to oseltamivir.
• However, some evidence of resistance to oseltamivir has been
reported in H5N1 viruses isolated from some human H5N1
cases.
• Monitoring for antiviral resistance among avian influenza A
viruses is important.
52
53. Bird Flu cont…
Prevention of Avian Influenza A Virus Infections of Humans
Persons who work with poultry - hand hygiene, and using
appropriate personal protective equipment.
receive seasonal influenza vaccination and take
prophylactic antiviral medication during an outbreak
control response.
Exposed persons should be carefully monitored for
symptoms that develop during and in 7 days after their last
exposure to infected poultry or to environments potentially
contaminated with avian influenza A virus-
excretions/secretions. 53
54. Swine flu
Swine influenza (swine flu) refers to influenza caused by
any virus of the family Orthomyxoviridae, that is endemic
to pig (swine) populations.
Strains endemic in swine are called swine influenza virus
(SIV).
SIV can mutate into a form that allows it to pass from
human to human.
The strain responsible for the 2009 swine flu outbreak
is believed to have undergone this mutation
54
55. Swine flu cont..
When a new strain of flu starts infecting
people, and when it acquires the ability to pass
from person to person, it can spark a pandemic.
The last pandemic was in 1968 and killed about
1 million people.
Etiologic agent for the current swine flu
epidemic in humans – Influenza A (HINI)
virus 55
56. Magnitude and distribution
of swine flu
The disease first detected in Mexico in April
2009
As of November 29,2009, more than 207
countries had reported laboratory confirmed
cases
Number of confirmed cases is over 525,000
worldwide (up to Nov. 2009 –WHO report)
Number died - at least 8,768 56
57. Magnitude and distribution
cont..
Ethiopia – On June 20, 2009 the first 2
confirmed cases of swine flu reported
Both were students who returned from
U.S
More cases were reported after that
57
58. Magnitude and distribution cont..
On July 10, 2010 WHO declared that the H1N1 swine
flu pandemic is over.
WHO added that the world has now entered the "post-
pandemic period”
According to the July 2010 WHO statistics the virus
has killed more than 18,000 people since it appeared in
April 2009,
however they state that the total mortality (including
deaths unconfirmed or unreported) from the H1N1
strain is "unquestionably higher”
58
59. Transmission of swine flu
Swine flu is spread when infected
person coughs or sneezes
human to human transmission almost
similar to SARS
59
61. Signs and symptoms
are similar to regular flu
Common symptoms:
– fever, cough, sore throat,
– body aches, headache, chills, fatigue.
Some people have reported diarrhea and vomiting.
Common symptoms
Fever
Cough
muscle pain and fatigue.
61
62. How long is someone infectious
with swine flu?
12 hours before signs and symptoms
develop up to 5 days from the start of
their illness.
People are most infectious during the
time they have symptoms.
62
64. Prevention and control
Covering nose and mouth with a tissue upon
coughing and sneezing
proper disposal of the tissue.
Avoiding contact with ill persons.
Avoiding the urge to touch nose, mouth and
eyes in general.
Staying home upon onset and for the
duration of symptoms.
Assuring adequate and thorough hand
washing and use of alcohol based hand
cleansers .
64
65. Prevention and control cont….
Encouraging pursuit of medical
evaluation at earliest onset of
symptoms.
Use of masks to those who are
exhibiting symptoms or who are ill.
Vaccination
Isolation
Quarantine?
65
66. Vaccination
Two kinds of vaccines:
1) H1N1 "flu shot"
• inactivated vaccine (containing killed virus).
• is approved for use in people 6 months of age
and older, including healthy people, people
with chronic medical conditions and pregnant
women.
66
67. Vaccination cont…
2) H1N1 nasal spray flu vaccine
• a vaccine made with live, weakened viruses
• is approved for use in healthy people 2
years to 49 years of age who are not
pregnant
• Antibodies produced in about 2 weeks after
vaccination
67
68. Who Should Get Vaccinated?
Five target groups
1) pregnant women
2) people who live with or provide care for infants
younger than 6 months
3) health care and emergency medical services
personnel
4) people 6 months through 24 years of age (especially
those with higher risk for influenza-related
complications like children younger than 5 years
and those who have high risk medical conditions)
5) people 25 years through 64 years of age who have
certain medical conditions that put them at higher
risk for influenza-related complications.
68
72. Prevention and control of
emerging diseases
There is an ongoing threat of new
infectious agents entering and causing
disease in human populations,
particularly from animal sources
72
73. Prevention and control cont…
There is a need for vigilance,
preparedness, and a high level of
international cooperation to detect &
respond to new infectious disease
threats that might emerge
WHO & others are currently working to
improve global capacity in this area
73
74. Global Outbreak Alert and Response
Network
In 2000, WHO created the Global
Outbreak Alert and Response Network
(GOARN), which has its headquarter in
Geneva
GOARN, which is intended to be an early
warning system receives a steady stream of
daily reports concerning possible outbreaks
from global network of informants 74
75. GOARN cont…
The network has proven extremely
useful as SARS, Avian influenza, and
other outbreaks have appeared
75
