An epidemiological study of sheep pox infection in Karnataka State, India.

Analysis of retrospective quantitative sheep pox epidemiological data from the Government Animal Husbandry Department, Karnataka, India, covering 24 years revealed significant information on sheep pox. The state has a dense sheep population including some valuable breeds. Data revealed the endemicity of the disease: there were a considerable number of outbreaks and attacks, high mortality and case fatality rates and low immunisation coverage. None of the years studied were free from infection. Temporally, the disease was most prevalent between November and May. Spatially, the disease was recorded in 19 out of 27 districts; in some of these districts sheep pox was highly endemic, in some it was endemic at low levels and in the remaining districts outbreaks occurred sporadically. Environmental factors influenced disease occurrence. Vaccine production met only one tenth of the requirement, and its peak utilisation was in the dry season.

A classical live attenuated vaccine for sheep pox.

A classical live attenuated sheep pox vaccine was prepared using the Ranipet strain of sheep pox virus (SPV) at the 50th passage in a secondary lamb testicular cell system. The TCID50 and RD50 were 10(9.63)/ml and 10(9.51)/ml. respectively. The SID50 of SPV challenge virus was 10(5)/ml. The vaccine was found to have no adverse effects in laboratory animals, and was safe and effective in SPV seronegative lambs. In the field, 660 sheep were vaccinated with an immunizing dose containing 1 x 10(2) TCID50. Randomly selected vaccinated sheep mounted good cell-mediated immunity and humoral responses as measured by glucose utilization test and serum neutralization test, respectively, for the study period of 6 months.