avian influenza - bird flu

World Health Organization Avian Influenza Bird flu World Health Organization Outline • What is influenza? • What is Avian Influenza? • What is the current situation? • Why is WHO concerned? • What needs to be done? World Health Organization Influenza (Flu) • Viral disease • Three types: A, B and C • Affect humans and other animals such as birds and pigs • Seasonal epidemics in temperate climates • Occasional pandemics (global epidemic) World Health Organization Influenza pandemics in the 20 th Century 1918: “Spanish Flu” 1957: “Asian Flu” 1968: “Hong Kong Flu” 40-50 million deaths 1 million deaths 1 million deaths • New virus strain • No immunity • Able to spread easily from person to person World Health Organization Structure of influenza A H (hemagglutinin) N (neuraminidase) World Health Organization (Karl G Nicholson, et al Lancet 2003; 362: 1733-45) • Many subtypes • 15 H and 9 N can mix in different combinations H1 H2 H3 H4 H5 H6 H7 H8 H9 H10 H12 H13 H14 H15 H11 N1 N2 N3 N4 N5 N6 N7 N8 N9 Influenza A viruses are classified by H and N types World Health Organization What is Avian Influenza? Bird Flu • Disease of wild birds, mainly waterfowl (e.g wild ducks) • Does not usually cause severe illness in wild birds • Domestic birds are more susceptible to some strains • Virus excreted in faeces and respiratory secretions • Human infections with avian influenza can occur, but rarely • Influenza pandemics are thought to be caused by viruses that are avian/human influenza hybrids World Health Organization Recent human infections by Avian Influenza Year Place Subtype Cases Deaths 1997 Hong Kong H5N1 18 6 1999 Hong Kong H9N2 2 0 2003 Hong Kong H5N1 2 1 2003 Netherlands H7N7 89 1 World Health Organization How might a pandemic strain appear? (First Mechanism) Migratory water birds Domestic birds World Health Organization How might a pandemic strain appear? (Second Mechanism) Migratory water birds Domestic birds [...]...How might a pandemic strain appear? (Third Mechanism) Migratory water birds Domestic birds World Health Organization Current avian influenza situation COUNTRY Korea Vietnam Japan Taiwan, Province of China Thailand Cambodia Hong Kong, SAR China Lao, PDR Pakistan Indonesia World Health Organization TYPE... poultry markets • If you do have contact with a high risk environment - wash your hands well • If you develop a fever (>37.5) – consult your doctor – stay at home • If you visit a patient - follow advice of hospital staff • WHO does not recommend any travel restrictions World Health Organization Food safety • No cases of avian influenza linked to eating poultry or eggs • Faecal contamination of the... or eggs • Faecal contamination of the surface of the eggs could occur: take care and wash eggs • Eggs from infected birds may contain the virus but the virus is inactivated by cooking • Observe good hygiene practices handling raw poultry meat • Influenza viruses are destroyed by heat • Influenza viruses are destroyed by household disinfectants World Health Organization Thank you World Health Organization... vaccine – Does not protect against H5N1 – Would reduce the chance of human / avian co-infection and reassortment • H5N1 vaccine – 6-8 months for vaccine production – Limited supply • Egg supply • 250 million doses in 2001 • Global shortage World Health Organization Antiviral drugs • Amantadine – Resistance • Oseltamivir (Tamiflu) – Expensive ($2 per capsule) – Limited availability – Must be used early... Human Cases (N=10) World Health Organization Why is WHO concerned? • Risk to humans from H5N1 • Risk of pandemic virus developing World Health Organization What do we have to do? • Stop transmission of avian virus to humans – Contain the outbreak in animals – Protect humans • Prepare for a virus with pandemic potential – Detect and investigate human cases – Characterise the virus – Prepare a vaccine . World Health Organization Avian Influenza Bird flu World Health Organization Outline • What is influenza? • What is Avian Influenza? • What is the current situation? • Why. combinations H1 H2 H3 H4 H5 H6 H7 H8 H9 H10 H12 H13 H14 H15 H11 N1 N2 N3 N4 N5 N6 N7 N8 N9 Influenza A viruses are classified by H and N types World Health Organization What is Avian Influenza? Bird Flu • Disease of wild birds, mainly waterfowl (e.g wild. wild birds • Domestic birds are more susceptible to some strains • Virus excreted in faeces and respiratory secretions • Human infections with avian influenza can occur, but rarely • Influenza