learn more facts about [zoonotic infections] , infectious diseases of humans that have animal origin.

Avian flu is caused by influenza A viruses that occur naturally among birds. There are different subtypes of these viruses because of changes in certain proteins [hemagglutinin and neuraminidase] on the surface of the influenza A virus and the way the proteins combine.Each combination represents a different subtype. The avian flu currently of utmost concern is the H5N1 subtype.

From Dr. Adesola Lajide - www.smartlaj.org