Avipoxviruses are normally only known as pathogens which cause avian pox in birds. They occur in many different bird species. Susceptibility of domestic and wild birds to avian pox infections is only partly understood. Avipoxviruses are primarily transmitted through insects and aerosols. Breeders also become infected through contaminated animals or food and possibly through blood-sucking parasites as well. Introduction into the population mainly happens when buying additional animals or following exhibitions. In wild birds, infection also occurs directly when picking each other’s beaks. There are different characteristic forms. The cutaneous form is the most common one and is characterised by papular efflorescences of the non-feathered skin areas (eyes, beak, comb, lower legs). Mild forms often develop benign skin tumours (head, legs) as a result of the long convalescence period (weeks/months). The mucous form is characterised by similar lesions on the mucosa of the beak cavity, tongue, pharynx or larynx (fowlpox/diphtheria). The septicaemic form typically displays general symptoms such as ruffled feathers, somnolence, cyanosis and anorexia without exterior pox lesions. Avian pox infections are usually not fatal (exception: canarypox => often fatal).