Fowl Pox, is a mild to severe, slow-spreading infection of birds, caused by viruses of the genus Avipoxvirus (family: Poxviridae). The disease, that bears economic importance in domestic poultry, is primarily apparent in either cutaneous («dry») or diphtheritic («wet») forms. The cutaneous form of the disease is mild and is characterized by nodular lesions on the non-feathered areas of the skin (or less typically as feather folliculitis, in the feathered areas of the skin). Inhalation/ingestion of virus-infected droplets/dust can lead to a more severe infection of the oropharyngeal cavity, called «diphtheritic infections». The latter is characterized by fibronecrotic, proliferative lesions on the mucous membranes of the respiratory and digestive tracts. Active immunity develops following natural infection or after immunization with live vaccines.