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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

Next is rodent flu

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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!