AVIAN INFLUENZA MUTATION, H5N1

Humans coincided with an epizootic

H5N1 is a type of avian influenza virus (bird flu virus) that has mutated through antigenic drift into dozens of highly pathogenic varieties. The first of these appeared in China in 1996 in birds and in Hong Kong in 1997 in Humans.

This infection of humans coincided with an epizootic (an epidemic in nonhumans) of H5N1 influenza in Hong Kong's poultry population. This panzootic (a disease affecting animals of many species esp. over a wide area outbreak was stopped by the killing of the entire domestic poultry population within the territory. The name H5N1 refers to the subtypes of surface antigens present on the virus.

Influenza A virus, the virus that causes Avian flu. Transmission electron micrograph of negatively stained virus particles in late passage.

Colorized transmission electron micrograph of H5N1 (golden) grown in Madin-Darby canine kidney cells (green). As of November 1, 2005, 122 cases of infections in humans, resulting in 62 deaths, have been confirmed outside of China (see Human cases). Thirteen countries across Asia and Europe have been affected. Additionally, more than 120 million birds have died from infection or been killed to prevent further infections.