Avian Influenza, more commonly called Bird Flu, is a highly contagious viral infection that affects fowl, mostly chickens and turkeys. It is caused by the H5N1 subtype of the Influenza A virus.
This subtype of the flu virus is deadly to birds, but does not usually affect humans. However, human infection with bird flu have been reported and documented. Research is mainly focused on vaccine development for human pandemics and prevention of human-to-human spread.