An atypical fowl pox outbreak in broilers in southern Brazil.

An unusual fowl pox outbreak occurred in two integrated broiler operations. The uncommon characteristic of this outbreak was that the pox lesions were manifested in the feathered parts of the body, mainly in the posterior dorsal area and external part of the thigh. Diagnosis was made by means of histopathology and virus isolation. Severe losses were incurred at the processing plant as a consequence of condemnation due to dermatitis. Vaccination of day-old chicks with mild fowl pox vaccine combined with Marek's disease (HVT) vaccine in the area of the outbreak appeared to be important in controlling the disease.