Theileria ovis (Piroplasmida: Theileriidae) Detected in Melophagus ovinus (Diptera: Hippoboscoidea) and Ornithodoros lahorensis (Ixodida: Argasidae) Removed From Sheep in Xinjiang, China

Abstract

Theileria spp. are tick-transmitted, intracellular apicomplexan protozoan parasites that infect a wide range of animals and, as such, can cause significant economic losses. The aim of the present study was to detect and analyze apicomplexan parasites from two different ectoparasites that were collected from Xinjiang Uygur Autonomous Region, China. The PCR-based detection of 18S rRNA indicated that Ornithodoros lahorensis specimens from Kashgar, Xinjiang, and Aksu were positive for Theileria spp., as were Melophagus ovinus specimens from Aksu. Meanwhile, phylogenetic analysis, based on the 18S rRNA gene sequences, revealed that the four amplified Theileria sequences could be attributed to T. ovis. To the best of our knowledge, this is the first study to report the detection of T. ovis DNA in M. ovinus and the first molecular identification study to confirm the detection of T. ovis in O. lahorensis in China. Accordingly, the present study extends the known distribution of T. ovis.

Vector-Borne Pathogens with Veterinary and Public Health Significance in Melophagus ovinus (Sheep Ked) from the Qinghai-Tibet Plateau

“…Historically, hard ticks were considered as the only and essential vector for Theileria spp. Our findings and similar studies conducted by Zhao [9] expand the potential vector spectrum of T. ovis. Herein, a high positive rate (89.1%, 82/92) of T. ovis DNA was demonstrated in M. ovinus in the present study, but this needs to be confirmed through more testing.…”

“…Theileria ovis are distributed widely in Asia, Europe, and Africa. In China, T. ovis has mainly been reported in animal, tick, and sheep keds from Xinjiang [9,21], Inner Mongolia [22], Qinghai [23], Sichuan [24]. Several reports have recently shown that there are two species of Theileria spp.…”

“…Several reports have recently shown that there are two species of Theileria spp. (T. ovis and T. luwenshuni) in M. ovinus [9,24]. Historically, hard ticks were considered as the only and essential vector for Theileria spp.…”

“…Melophagus ovinus serves as potential vectors of a variety of pathogens and has been reported to be responsible for the transmission of pathogenic organisms such as helminths, protozoa, bacteria, and viruses due to their blood-feeding behavior towards hosts [1,9]. M. ovinus was reported to mechanically transmit the Bluetongue virus in sheep [2].…”

“…Chu et al [6] reported Borrelia burgdorferi sensu lato in sheep keds in Tibet, China. Recently, in China, Anaplasma ovis [13], Rickettsia raoultii and R. slovaca [5], Theileria ovis [9], and Border disease virus (BDV) [14] have also been detected in M. ovinus in the Xinjiang Uygur Autonomous Region of northwestern China.…”