Sheep pox disease outbreaks in Madras Red and Mechery breeds of indigenous sheep in Tamilnadu, India

Sheep pox disease outbreaks were recorded among Madras Red (n = 145) and Mechery (n = 80) breeds of indigenous sheep on three farms in Tamilnadu. Over both breeds, adult mortality rate ranged from 2.66% to 37.5% and lamb mortality ranged from 10% to 17.33%. However, mortality was more in Mechery sheep (50% overall; 37.5% adults, 12.5% lambs) than in Madras Red sheep (24.28% overall; 10.34% adults, 13.79% lambs). The clinical signs observed were high fever, anorexia, respiratory distress, mucopurulent nasal discharge and in a few cases diarrhoea. Cutaneous lesions were mainly observed around nostrils, eyes, lips, ears and in the abdomen. Most of the lesions were covered with purulent materials and on cleaning with sterile swabs, fresh wounds were observed. Dry scabs were also observed over the oral commissure and maxillary areas, which on removal exposed fresh wounds. Important observations on necropsy were severe nodular lesions in the lungs and intestine. The disease was diagnosed as sheep pox by agar gel immunodiffusion test, isolation of virus and its neutralization in BHK21 cells by specific antiserum and by electron microscopy.