Epidemiology of ovine theileriosis in Ganan region, Gansu Province, China.

The epidemiology of ovine theilreiosis in Gannan Tibet Autonomous Region was investigated. The results of these studies indicate that this disease is endemic in the following counties of Gannan where the vector tick was identified as Haemaphysalis qighaiensis: Luqu, Xiahe, Hezuo, Zhuoni, Lintan, Diebu, Maqu. The disease mainly occurred from March to May and some cases also occurred in September and October. The incidence rates in lambs of sheep brought from areas free of the disease were high. On average, the incidence and mortality rates were 60.8% and 81.5% respectively. In adult sheep, the incidence and mortality rates were 17.12% and 65.78% respectively. The mean incidence rate of young goats was 40% and the mortality was 85.71%. The incidence rate for adult goats was 8.06% and the mortality was 73.33%. During the carrier period, the infection rates of lambs, young goats, adult sheep and adult goats were 91.7%, 64.29%, 63.13%,and 20% respectively.