This document discusses avian influenza (bird flu) and pandemic influenza. It begins with background on influenza viruses and past pandemics. It then focuses on bird flu, including the H5N1 strain that has infected birds and humans. The document covers epidemiology of avian influenza, symptoms and diagnosis in humans, and the pandemic risk posed by an influenza virus acquiring easy human-to-human transmission. It concludes with recommendations for prevention, including avoiding sick birds, and global preparedness efforts led by organizations like WHO.

1. BIRD FLU
AVIAN INFLUENZA
Presented By: Dr. Ghulam Mustafa

2. Contents
• What is Influenza?
• History of Influenza.
• Types of Influenza viruses.
• What is Bird Flu?
• Bird Flu in India.
• Epidemiological determinants.
• Clinical feature and Diagnosis.
• Pandemic Risk and phases of pandemic.
• Prevention and Preparedness.

3. What is influenza?
• An acute respiratory illness resulting from infection
with an influenza virus.
• Highly infectious.
• Can spread rapidly from person to person.
• Some strains cause more severe illness than others.

4. History of influenza
• 412 BC – first mentioned by Hippocrates.
• 1580- first pandemic described.
• 1580-1900- 28 pandemics.
• 1918- Spanish flu (H1N1), 20-40 million deaths.

5. • 1957-Asian flu (H2N2) , 1million deaths.
• 1968- Hong Kong flu (H3N2), 1 million deaths.
• 1997- Local Outbreak- Hong Kong (H5N1)
• 2009 – Pandemic (H1N1)

6. Types of influenza viruses
• Four main types: Influenza A, B, C and D
• A viruses- infect birds and other animals, as well as
humans.
• B viruses- cause seasonal epidemics in humans.
• C viruses can infect humans and pigs.
• D viruses- not known to cause illness in humans.

7. • Influenza virus is an RNA virus –Orthomyxoviridae
family.
• On the basis of surface proteins (Haemagglutinin:
HA) and (Neuraminidase: NA) Influenza Type A
virus is classified into sub types.
• Various types of combinations are possible.
• For example HINI Virus has an HA1 protein and an
NA1 protein only.

8. Influenza A HA and NA Subtypes
H15, H16
H14
H13
H12
H11
H10
H3
H2
H1
H9
H8
H7
H6
H5
H4
N9
N8
N7
N6
N5
N3
N4
N2
N1

11. What is Bird Flu?
• A contagious disease of animals caused by viruses that
normally infect birds such as chicken and Turkeys.
• Avian influenza viruses are highly species specific.
• They cause two forms of diseases:
• Low pathogenic-low egg production, ruffled feather
mild symptoms.
• High pathogenic – with mortality reaching 100% within
48 hours.

12. H5 N1 out break
• Largest and most severe out break on record.
• It Caused an estimated 150 million birds death.
• It is still endemic in many SEA countries.
• First time when humans have contracted flu from
birds.

13. • Since 2003 this virus has spread to Europe and
Africa, that led to many human deaths.
• In 2013 human infections with A (H7N9) virus were
reported in china.
• Other viruses known for sporadic human infections
are A(H7N7) and A (H9N2).
• H1N1,H2N2,H3N2 are currently in circulation
among humans.

14. Bird flu in India
• No case of bird flu in humans has been detected so
far, according to the Union health ministry.
• The department of animal husbandry has reported 25
episodes of H5N1 bird flu in poultry in 15 states
from 2006 (when the first outbreak occurred in
Maharashtra and Gujarat) till 2015.

15. • 2021 outbreaks of Avian Influenza (bird flu).
• The flu has been confirmed in 14 states so far
including ––Jammu and Kashmir.
• In 5 districts of Kashmir valley.

16. Epidemiological determinants
• Agent: Influenza virus type A
• Reservoir of infection: Wild aquatic birds(ducks,
geese) are natural reservoir. Domestic ducks (silent
reservoir).
• Source of infection: Infected birds- No direct person
to person contact.(WHO)

17. • Host Factors:
• Age and Sex: All ages and Both sexes are
susceptible.
• Immunity: No one is immune (No cross protection
immunity).
• Incubation period: varies from virus to virus but
longer than seasonal flu (2 days)---average 5 days.

18. Mode of Transmission
• Direct contact with infected birds or surfaces and
objects contaminated by their faeces.

19. Risk to human health
• Two main risk for human health are:
• First: Avian virus cause vey severe disease in
humans.
• In H5N1 outbreak half of those infected with virus
had died.
• Second: Virus has potential to change into a form
that is highly infectious for humans and can spread
easily.

20. Pathogenesis and Clinical features
• Involvement of respiratory tract, with inflammation and
necrosis of superficial epithelium.
• It may follow secondary bacterial infection.
• Symptoms are :
• Cough.
• Fever.

21. • Chills.
• Aches.
• generalized weakness.
• Complications are:
• Acute sinusitis.
• Otitis media.
• Purulent bronchitis.
• Pneumonia- most dreaded.
• Gastro intestinal symptoms – frequent with H5N1.

22. Laboratory Diagnosis
• Respiratory specimen should be collected within
first 4-5 days of illness.
• Rapid influenza diagnostic tests.-lower sensitivity.
• RT-PCR.
• Viral isolation- culture.
• Four fold rise in virus specific neutralizing
antibodies.

23. Pandemic risk
• Three conditions are required for start of an Avian
influenza epidemic:
• A new influenza virus emerge.
• It infects humans, causing serious illness.
• It spreads easily and sustained among humans.
• First and second conditions have all ready been met.

24. Phases of a Pandemic
• Phase 1: Predominantly animal to animal transmission – few
human cases.
• Phase 2: An animal influenza virus capable of causing
infection among humans.
• Phase 3:Small out break among close population.
• Phase 4: Sustained human to human transmission.
• Phase 5:Spread across two or more countries in one of the
WHO region.
• Phase 6: Spread across more than one WHO region.

25. Prevention
• Eliminate the virus from birds-best but difficult.
• Depopulation/Culling/Stamping out.

26. WHO Recommendations
• WHO continues to recommend that travelers to
affected areas should avoid contact with live
animal markets and poultry farms, and any free-
ranging or caged poultry.
• Large amounts of the virus are known to be
excreted in the droppings from infected birds.
• Populations in affected countries are advised to
avoid contact with dead migratory birds or wild
birds showing signs of disease.
http://www.who.int/csr/disease/avian_influenza/en

27. • Isolation.
• Quarantine.
• Self shielding.
• Social distancing.
• Snow days.
• Personal Hygiene.

28. • Vaccine:
• Vaccine are produced every year for seasonal
influenza.
• These vaccine will not protect against pandemic
influenza.
• Drugs:
• Oseltamivir (Tamiflu).
• Zanamivir (Relenza).

29. Preparedness for Pandemic
• WHO have a stockpile of antiviral medication.
• GISRS-Global Influenza Surveillance and Response
System.
• More than 40 countries including India have
developed preparedness plan.
• India has a stockpile of more than 10million doses
of Tamiflu.

30. References
• Park’s Textbook of Preventive and Social Medicine.
• Centre for Disease Control (CDC)
• World Health Organization (WHO)
• Google Images

31. Thank You