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Melophagus ovinus (sheep ked) is a hematophagous ectoparasite that mainly parasitizes sheep. In addition to causing inflammation, wool loss, and skin damage to the animal hosts, M. ovinus also serves as a vector for a variety of pathogens and is highly likely to participate in the life and transmission cycle of pathogenic organisms. Herein, we investigated the presence and molecular characterization of vector-borne pathogens in M. ovinus from Qinghai-Tibet Plateau, China. A total of 92 M. ovinus pools collected from the Qinghai province of China were screened for the presence of selected vector-borne pathogens. The overall positive rate of A. ovis, A. bovis, A. phagocytophilum, and T. ovis in M. ovinus was 39.1%, 17.4%, 9.8%, and 89.1%, respectively. All of the samples were negative for Border disease virus (BDV), other Anaplasma species, Babesia spp., Rickettsia spp., and Borrelia spp. Co-infection of different Anaplasma species and T. ovis occurred in 51.2% of all samples with T. ovis. The positive rates of A. ovis, A. bovis, and A. phagocytophilum in different regions and altitudes of the sampling sites were significantly different. Sequence and phylogenetic analysis of target genes confirmed their identity with corresponding pathogens. Our results elucidate the occurrence and molecular characterization of Anaplasma spp. and Theileria spp. in M. ovinus, which could act as potential zoonotic reservoirs. To the best of our knowledge, this is the first report of the detection of A. bovis and A. phagocytophilum DNA in M. ovinus. This study gives the first extensive molecular survey of vector-borne pathogens with veterinary and public health significance in M. ovinus from the Qinghai-Tibet Plateau, China.

Livestock husbandry is vital to economy of the Tarim Basin, Xinjiang Autonomous Region, China. However, there have been few surveys of the distribution of ixodid ticks (Acari: Ixodidae) and tick-borne pathogens affecting domestic animals at these locations. In this study, 3,916 adult ixodid ticks infesting domestic animals were collected from 23 sampling sites during 2012-2016. Ticks were identified to species based on morphology, and the identification was confirmed based on mitochondrial 16S and 12S rRNA sequences. Ten tick species belonging to 4 genera were identified, including <i>Rhipicephalus turanicus</i>, <i>Hyalomma anatolicum</i>, <i>Rh. bursa</i>, <i>H. asiaticum asiaticum</i>, and <i>Rh. sanguineus</i>. DNA sequences of <i>Rickettsia</i> spp. (spotted fever group) and <i>Anaplasma</i> spp. were detected in these ticks. Phylogenetic analyses revealed possible existence of undescribed <i>Babesia</i> spp. and <i>Borrelia</i> spp. This study illustrates potential threat to domestic animals and humans from tick-borne pathogens.

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