Molecular epidemiological study on tick-borne pathogens in Qinghai Province, Northwestern China

Recently, there has been a continuous stream of reports on emerging tick-borne pathogens affecting humans. Qinghai Province, located in the northweastern region, is one of China's major pastoral areas, providing a suitable environment for ticks' survival and transmitting tick-borne pathogens. Here, we collected 560 free-living and parasitic ticks from 11 locations in Qinghai Province using the flag-drag method or tweezers, identifying them as belonging to 4 species of ticks. The overall positivity rate for tick-borne pathogens was 51.61 %, comprising Rickettsia (34.64 %), Anaplasma (5.00 %), Ehrlichia (2.14 %), Borrelia burgdorferi sensu lato (BBSL) (7.50 %), Babesia (0.18 %), and Theileria (5.89 %). Sequencing revealed the presence of 7 species of Rickettsia, 4 species of Anaplasma, 2 species of Ehrlichia, 2 species of BBSL, 1 species of Babesia, and 3 species of Theileria. Among the ticks, 6.43 % were co-infected with 2 pathogens, while 0.36 % exhibited co-infection with 3 pathogens. Significant correlations (P < 0.05) were observed between the prevalence of tick-borne pathogens and factors including tick species, sex, developmental stages, parasitic status, and blood-feeding status. The results highlight the diverse distribution of tick-borne pathogens in Qinghai Province, posing a significant threat to both local animal husbandry and human health. It underscores the need to enhance systematic monitoring of tick-borne pathogens in the local population and livestock.