Fowlpox virus (FPV), also referred to as avian pox virus (APV) is of the genus Avipoxvirus which is within the Poxviridae family. APV affects a wide range of bird species (approximately 60 different species from 20 different families) both domestic and wild, worldwide. APV contains several similar virus strains that have the ability to infect several groups or species of birds and others are species-specific.
Outbreaks of APV are influenced by environmental conditions including temperature, humidity, moisture and protective cover. It is occurs more commonly when mosquito populations are more abundant, as they serve as a main vector for transmitting the virus between birds.