Detection of Theileria spp. in ticks, sheep keds (Melophagus ovinus), and livestock in the eastern Tibetan Plateau, China

Theileriaspecies, with a broad geographic distribution, infect a wide range of both domestic and wild animals and are transmitted by ixodid ticks. Currently, there is no comprehensive report regarding the distribution ofTheileriaspp. in the eastern Tibetan Plateau, especially in Ganze Tibetan autonomous prefecture (153,700 km(2)) and Ngawa Tibetan and Qiang autonomous prefecture (84,242 km(2)) of Sichuan province, China. In this study, we collected blood samples from yaks (n = 144) (Bos grunniens), Tibetan sheep (n = 92), and Tibet horses (n = 142) in Ganze and Ngawa. Theileria sinensis,T. luwenshuni, andT. equiwere the dominantTheileriaspecies detected in yaks, Tibetan sheep, and horses with the total infection rates of 25.7% (37/144), 75.0% (69/92), and 51.4% (73/142), respectively. For ectoparasites,T. luwenshuniwas the onlyTheileriaspecies detected in sheep keds (Melophagus ovinus) with an infection rate of 30.8% (8/26). The total infection rates ofT. sinensisinHaemaphysalis qinghaiensis,Dermacentor everestianus, andRhipicephalus micropluswere 34.6% (36/104), 34.0% (17/50), and 51.3% (58/113), respectively.Theileriaspp., belonging toT. sergenti/buffeli/orientalisgroup, were only detected inR. micropluscollected in Danba county of Ganze with a total infection rate of 39.9% (19/48). Our results provide important data of the epidemiology ofTheileriaspp. in livestock and ectoparasites and will assist with the implementation of measures to control theileriosis transmission in eastern Tibetan Plateau, China.