[How dangerous is avian flu for mankind?]

Abstract

Background: Avian influenza, an infectious disease of birds, is caused by type A strain of the influenza virus. The disease, which was first identified in Italy more than 100 years ago, occurs worldwide. Avian influenza viruses are mainly distributed by migratory birds. Various animals like birds, pigs, horses, sea mammals and, finally, humans are susceptible to influenza A viruses. The high possibility of genomic changes like gene shift and drift are caused by the segmented RNA genome.

Epidemiology: Since December 2003 a total of eleven countries (Vietnam, Thailand, Indonesia, Cambodia, China, Laos, Japan, Malaysia, South Korea, Russia, Kazakhstan) have reported outbreaks of highly pathogenic avian influenza A (H5N1) virus affecting poultry. Mongolia reported detection of H5N1 virus in migratory birds in August 2005, and actually also Romania and Turkey. During the avian flu outbreak approximately 150 million birds have died or been culled. The virus also jumped to humans; a total of 117 H5N1 cases in humans have been reported to the WHO, in four countries (Vietnam, Thailand, Indonesia, and Cambodia), 60 patients of them died. That avian influenza could also be a threat to humans has been known since 1997.

Outlook: Because of the natural virus reservoir like wild and/or domesticated ducks and others, actually there is rarely no chance to eradicate influenza. Furthermore, the virus could mutate and jump to humans with the threat of a global influenza pandemic. However, this is a statistically rare event.