What is avian influenza?

Avian influenza (AI), also known as bird flu, is a highly contagious viral disease of chickens and turkeys, but many other birds are also susceptible. A basic distinction can be made between two groups of avian influenza viruses, the so-called low pathogenic ("less pathogenic") and the highly pathogenic ("very pathogenic") influenza viruses. The highly pathogenic avian influenza viruses (e.g. H5N8) can lead to high animal losses in poultry, for example chickens or turkeys. Low pathogenic influenza viruses, on the other hand, often cause little or no signs of illness, as these viruses lack the properties to cause severe disease. Only infection with highly pathogenic avian influenza viruses is referred to as avian influenza.