Avian Influenza (AI) or "Bird Flu" is a highly contagious viral infection which can affect all species of birds.
Influenza infections in birds are divided in two groups on the basis of their ability to cause disease:
Highly Pathogenic Avian Influenza (HPAI) causing serious disease with high mortality and
Low Pathogenic Avian Influenza (LPAI) causing in general a mild disease.
Free-living birds may carry influenza viruses without becoming ill due to a natural resistance.
It is known that wild waterfowl present a natural reservoir for these viruses and can be responsible for the primary introduction
of infection into domestic poultry.