Bird flu

Avian Influenza

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 K ong 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

9. 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.

10. 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.

11. 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.

12. 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.

13. 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.

14. 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)

15. 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.

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

17. 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.

18. 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.

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

20. 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.

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

22. 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.

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

24. 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

25. Isolation. Quarantine. Self shielding. Social distancing. Snow days. Personal Hygiene.

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

27. Preparedness for Pandemic WHO have a stockpile of antiviral medication. GISRS-Global I nfluenza Surveillance and Response S ystem. More than 40 countries including India have developed preparedness plan. India has a stockpile of more than 10million doses of Tamiflu.

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

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