The document discusses the threat of a potential bird flu pandemic. It notes that the H5N1 avian influenza virus has caused human deaths in Asia and has a high mortality rate. Experts fear it could mutate and spread efficiently between humans, causing a global pandemic. Key risks include asymptomatic infection, limited immunity, and potential for the virus to reassort genes allowing human-to-human transmission. Proper management requires vaccines, social distancing, antiviral drugs, and pandemic preparedness. However, it remains unknown whether or when the virus may gain efficient human transmission.

1. Will it be just a scare … or a scar on human history? Bird flu

2. It has become the headlines of news channels It’s circulating largely among bird flocks in Asia … Thailand on Monday 7/11/05 reported its 20 th human victim since 2003 … China reports sixth case in this year … It’s bird flu …that’s spreading through ! High mortality rate : 62% human fatal cases WHO

3. “ A pandemic of bird flu” Health experts fear that the avian flu virus could mutate and acquire the ability to infect large numbers of people ... Should that happen, without immediate and effective interventions to contain it … the Global Impact could be incalculable

12. REASSORTMENT : Pigs New subtype influenza

13. REASSORTMENT : Humans New subtype influenza

15. Circulating influenza strains and pandemics in 20 th century 1920 1940 1960 1980 2000 H1N1 1918: “Spanish Flu” 20-40 million deaths WHO H2N2 1957: “Asian Flu” 1 million deaths H3N2 1968: “Hong Kong Flu” 1 million deaths

20. NEJM 2005 Fusion with host cell Attachment to host cell receptor – sialic acids Virus Replicates its genetic material inside host cell Viral progeny Attached to host cell receptor-sialic acids Releases the attached progeny; removing sialic acid LIFE CYCLE OF INFLUENZA H spike N spike M 2 protein NEURAMINIDASE INHIBITORS Prevent the virus from infecting new cell