Highly Pathogenic Avian Influenza A (H5N1) in Birds and Other Animals

Birds and Poultry

Highly pathogenic (deadly) avian influenza A (H5N1) virus – also called HPAI H5N1 virus – is a virus that occurs mainly in birds, is highly contagious among birds, and can be deadly, especially domestic poultry.

HPAI H5N1 virus infections in poultry and wild birds, resulting in high mortality, have been detected in Asia, the Middle East, Europe, and Africa since December of 2003. The highly pathogenic avian influenza A (H5N1) epizootic (animal outbreak) is not expected to diminish significantly in the short term. H5N1 viruses are spreading more widely in poultry and wild birds and H5N1 virus infections among domestic poultry have become endemic in certain areas. As of 2011, the U.S. Food and Agriculture Organization considers six countries to be endemic for HPAI H5N1 virus in poultry (Bangladesh, China, Egypt, India, Indonesia, Vietnam). Outbreaks of H5N1 virus among poultry and infections in wild birds can also occur in non-endemic counties.

Other Animals

H5N1 viruses have been detected in other animals as well (see list below). Infection of animals other than birds with these viruses has been self-limiting. As H5N1 viruses continue to evolve, other mammals may become infected.

• H5N1 virus infection among pigs in China, Indonesia and Vietnam;
• H5N1 virus infection of cats (experimental infection of housecats in the Netherlands, isolation of H5N1 virus from domestic cats in Germany, Thailand, and detection of H5N1 viral RNA in domestic cats in Iraq and Austria);
• H5N1 virus infection of dogs (isolation of H5N1 virus from a domestic dog in Thailand);
• Isolation of H5N1 viruses from tigers and leopards at zoos in Thailand;
• H5N1 virus infection in a wild stone marten (a weasel-like mammal) was reported in Germany and in a wild civet cat in Vietnam.

View the update on avian influenza in animals from the World Organization for Animal Health (OIE) website.

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