Molecular detection of Bartonella in ixodid ticks collected from yaks and plateau pikas (Ochotona curzoniae) in Shiqu County, China

BACKGROUND: Bartonella bacteria have been associated with an increasingly wide range of human and animal diseases. These emerging pathogens have been identified as being globally dispersed. Ticks and small rodents are known hosts of Bartonella and play a significant role in the preservation and circulation of Bartonella in nature. This study investigated the occurrence of hoist spp. in ticks (Acari: Ixodidae) and plateau pikas (Ochotona curzoniae) in Shiqu County, which is located on the eastern Qinghai-Tibetan Plateau in China. Shiqu County is spread over approximately 26,000 km(2), with an average altitude of above 4200 m and a vast area of pastureland. RESULTS: A total of 818 ticks (Dermacentor everestianus, 79.0%, 646/818; Haemaphysalis qinghaiensis, 21.0%, 172/818) were collected from yaks in 4 villages of Shiqu County. Only Bartonella melophagi was detected in tick samples, with a total prevalence of 30.1% (246/818). The infection rates of B. melophagi in ticks from Arizha, Maga, Derongma, and Changxgma were 4.8, 76.8, 12.5, and 18.0%, respectively. The infection rate of B. melophagi in Maga was higher (p < 0.01) than those in other villages. Regarding plateau pikas, the total infection rate of Bartonella spp. was 21.7% (62/286), with 16.7% (12/72), 30.9% (25/81), 13.8% (9/65), and 23.5% (16/68) in Arizha, Maga, Derongma, and Changxgma, respectively. Finally, B. queenslandensis and B. grahamii were detected in plateau pika. No significant difference was observed (p > 0.05) in the infection rates between these study sites. CONCLUSION: To date, only D. everestianus and H. qinghaiensis were found in Shiqu County with high infection of Bartonella spp. in the ticks and plateau pika. The threats of Bartonella species to public health should be closely monitored.