Vector-Borne Pathogens With Veterinary and Public Health Significance in Melophagus Ovinus (Sheep Ked) From the Qinghai-Tibet Plateau

Background: 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. MethodsHerein, we investigated the presence and molecular characterization of vector-borne pathogens in M. ovinus from Qinghai-Tibet Plateau, China. ResultsA total of 92 M. ovinus pools (n=276) collected from Qinghai province of China were screened for the presence of selected vector-borne pathogens. The overall prevalence 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 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 region and altitude of the sampling sites were significantly different. Sequence and phylogenetic analysis of target genes confirmed their identity with corresponding pathogens. ConclusionOur results elucidate the occurrence and genetic diversity 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.