Pathological and molecular diagnosis of avian pox in backyard chickens in Khorram Abad

Avian pox is a world-wide, contagious and common viral disease of numerous domestic and wild bird species and is generally host specific for different species of birds. In the present study, avian pox infection was identified in backyard chickens of Khorramabad with clinical signs including anorexia, depression and ruffled feathers and morbidity and mortality rates of 50% and 5 to 20%, respectively in affected flocks. On clinical examination, the lesions were observed as wart-like nodules with different sizes on the comb, wattle and around the eyelids. In addition, in some affected birds, fibrinonecrotic lesions in oral mucosa, pharynx and epiglottis was observed. Histopathologic examination of lesions revealed degeneration, vacuolization and hyperplasia of epithelial cells associated with intracytoplasmic eosinophilic inclusion bodies (Bollinger bodies). Based on the phylogenetic analysis, the isolated fowl poxvirus was classified in a different subclade far from other Iranian isolates and near to isolates from Tanzania, Egypt and Germany. The evaluation of avian pox situation in backyard chickens is very important because of its economic losses in rural areas and their role as sources of infection in commercial poultry.