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Avian InfluenzaThe term Bird Flu is used to describe two different but related diseases – Avian Influenza which is a long established disease of birds and Pandemic Human Influenza Avian Influenza Avian Influenza (AI) otherwise known as Bird Flu is a viral disease affecting the respiratory, digestive and /or nervous system of birds. AI virus infecti on can occur in most, if not all, species of birds, both domestic and wild. These viruses vary widely in their ability to cause disease (pathogenicity); AI may be Highly Pathogenic (HPAI) or Low Pathogenic (LPAI). Most outbreaks are LPAI which causes little or no clinical signs in affected birds. LPAI does not usually affect humans. Infected wild species of birds may not develop clinical disease, but some influenza viruses can cause severe illness or death in chickens, turkeys and guinea fowl. How Is Avian Influenza Spread? Water fowl (ducks) and migratory birds act as host for influenza viruses by carrying the virus in their bodies and shedding it. Infected birds shed virus in saliva, nasal secretions and faeces. AI is spread among susceptible birds when they have contact with contaminated nasal, respiratory and fecal material from infected birds. It can also be spread by manure, equipment, vehicles, egg flats, crates, and people whose clothing or shoes have come in contact with the virus. The viruses can remain viable at moderate temparatures for long periods in the environment and can survie indefinitely in frozen material. One gram of contaminated manure can contain enough virus to infect one million birds. Transmission to Humans The first documented infection of humans with an AI virus occurred in Hong Kong in 1997, when the H5N1 strain caused the severe respiratory disease in 18 humans, of whom 6 died. The 2004-2005 outbreak in South East Asia, has so far claimed the life of over 65 people. Signs of AI infection in man may include:
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