Post on 18-Dec-2015
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Mohamed M. B. Alnoor
CHP400COMMUNITY HEALTH PROGRAM-II
Avian Influenza
H5N1
Epidemiology & Control
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Avian Influenza
Content
• Definition• Transmission in birds• Infection and Disease in poultry• Epidemiology
• Prevention
• Features in humans
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Avian Influenza
Definition
• Avian influenza is an infection caused by (bird) influenza viruses
naturally occurring among birds. esp the waterfowl
Avian Influenza H5N1
ducksgeese
swansالبـط
األوزالبجــع
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Avian Influenza
Definition
• The complete host range is not known
• Wild birds worldwide carry the viruses in their intestines,
but usually do not get sick from them.
Avian Influenza H5N1
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Avian Influenza
Transmission in birds
secretions excretions surfaces
Avian Influenza H5N1
Infected birds shed influenza virus in: saliva nasal secretions feces.
Susceptible birds become infected when they have contact with contaminated
For 10 days
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Avian Influenza
AIV is not normally found in domestic ducks, chicken and turkeys
Transmission of AIV from wild birds to domestic poultry species occurs commonly (ducks>turkeys>chicken)
AIV on rare occasions may become established in chicken and turkeys and result in serious disease outbreaks
AIV once adapted to chicken and turkeys can be difficult to eradicate
Infection in PoultryAvian Influenza H5N1
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Avian Influenza
Two main forms of disease:
a- The low pathogenic :can go undetected and usually with mild symptoms
b-The highly pathogenic :spreads more rapidly through flocks of poultry. It may affect multiple internal organs and has a mortality :90-100% often within 48 hours.
Avian Influenza H5N1Disease in Poultry
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Avian Influenza
Epidemiology WHO: ≤ 3/2013 :622 human cases of avian
influenza A (H5N1) in:• Asia, Africa, the Pacific, Europe and the Near
East. Indonesia and Vietnam have reported the highest number of cases.
• Case Fatality Rate(371/622) ≈ 60%.
• The majority of cases have occurred among children and adults <40 years.
Avian Influenza H5N1
E x p o s u r eE x p o s u r e
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Avian Influenza
• Mortality was highest in cases aged 10-19 years old.
• Significant risk factors : direct contact with sick or dead poultry or wild birds, or visiting a live poultry market.
• Most human H5N1 cases have been hospitalized late in their illness with severe respiratory disease.
• A small number of clinically mild H5N1 cases have been reported.
EpidemiologyAvian Influenza H5N1
• bird-to-human transmission
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Avian Influenza
Children and young adults Abdominal symptoms common
Avian Influenza H5N1
Diarrhoea Vomiting Abdominal pain
Pneumonia Lymphopenia Deranged LFTs
Features in humans
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Avian Influenza
Transmission&Prevention
Leaves original host
Survives in transit
Escapes host defensesMultiplies and causes illness
Facemasks, cough etiquette
Cleaning, hand washing
Social distance, cohorting
Facemasks, handwashing
Vaccination
Delivered to a susceptible host
Reaches a susceptible part of the host
Avian Influenza H5N1
The virus
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Avian Influenza
Conclusion
Avian Influenza H5N1
• H5N1 is a rare disease in people.
• The virus does not infect humans easily.
• Scientists are concerned that the virus one day could spread easily from
person to person.
• High case fatality rate
• No pandemic so far!