The spread of the H5N1 bird flu epidemic in Asia in 2004
H5N1 avian influenza has spread to eight countries in eastern Asia including China, Japan, South Korea, Vietnam, Laos, Cambodia, Thailand, and Indonesia in early 2004. This H5N1 influenza A virus is extremely virulent in poultry including chickens and ducks, killing millions of birds throughout the region. Additionally this virus has transmitted to humans (mainly children) in Vietnam, Cambodia, and Thailand, killing 54 of 100 diagnosed persons. To control this epidemic hundreds of millions of chickens and ducks have been culled. One genotype of H5N1 designated “Z” has become dominant in Asia. This viruswas first detected in wild birds in Hong Kong in November 2002 and was antigenically distinct from H5N1 viruses isolated from 1997 to early 2002 and lethal for aquatic birds.
The H5N1 virus infecting humans and poultry in Asia in 2004 is an antigenic variant of the Z genotype. Here we consider the possible role of migrating birds in the evolution and spread of the H5N1 influenza A virus throughout Asia. We conclude that the available information is consistent with a role for migrating birds but limited information is available and that serological studies are urgently needed on migrating birds worldwide. The prospect is that this H5N1/04 influenza A virus will become endemic in poultry in eastern Asia and will be a continuing threat to animal and human health. It is also projected that a human H5N1 vaccine will eventually be needed.
KeywordsH5N1 Virus Wild Bird Migrate Bird Aquatic Bird Grey Heron
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- 2.Banks J, Seidel ES, Moore E, Plowright L, Piccirillo A, Capua I, Cordioli P, Fioretti A, Alexander DJ (2001) Changes in the haemagglutinin and the neuraminidase genes prior to the emergence of highly pathogenic H7N1 avian influenza A viruses in Italy. Arch Virol 146: 963–973PubMedCrossRefGoogle Scholar
- 4.Carey GJ, Chalmers ML, Diskin DA, Kennerley PR, Leader PJ, Leven MR et al (2001) The avifauna of Hong Kong. Hong Kong Bird Watching Society, Hong KongGoogle Scholar
- 8.del Hoyo J, Elliott A, Sargatel J (1992) Handbook of the birds of the world, vol 1. Lynx Edicions, BarcelonaGoogle Scholar
- 9.Ellis TM, Bousfield RB, Bissett LA, Dyrting KC, Luk GS, Tsm ST, Sturm-Ramirez K, Webster RG, Guan Y, Malik Peiris JS (2004) Investigation of outbreaks of highly pathogenic H5N1 avian influenza in waterfowl and wild birds in Hong Kong in late 2002. Avian Pathol 33: 492–505PubMedCrossRefGoogle Scholar
- 16.Hien TT, Liem NT, Dung NT, San LT, Mai PP et al (2004) Avian influenza A (H5N1) in 10 patients in Vietnam. N Engl J Med Epub Feb 25Google Scholar
- 30.Panigrahy B, Senne DA, Pedersen JC (2002) Avian influenza A virus subtypes inside and outside the live bird markets, 1993–2000: a spatial and temporal relationship. Avian Dis 46: 2Google Scholar