Prevalence of Multiple Tick-Borne Pathogens in Various Tick Vectors in Northeastern China.

Tick-borne bacteria and protozoa can cause a variety of human and animal diseases in China. It is of great importance to monitor the prevalence and dynamic variation of these pathogens in ticks in ever-changing natural and social environment. Ticks were collected from Heilongjiang and Jilin provinces of northeastern China during 2018-2019 followed by morphological identification. The presence of spp., spp., spp., spp., spp., and spp. was examined by PCR and Sanger sequencing. The obtained sequences were subjected to phylogenetic analysis through Mega 7.0. Statistical analysis was performed using SPSS 24.0. A total of 250 ticks from 5 species of 3 genera were collected. and ticks carried more species of pathogens than , and the pathogens detected in varied significantly among different sampling sites. The infection rates of spp., spp., spp., spp., spp., and spp. were 41.2%, 0, 2.0%, 7.2%, 1.2%, and 7.2%, respectively. Twelve pathogens were identified, among which (29.6%), (9.2%), and (4.4%) were the three most common ones. had its dominant vector, that is, had high infection rates in and , in , and in . Interestingly, unclassified species were observed, including a sp., an sp., a sp., and a sp. Coinfections with different pathogens were identified in 9.2% of all tested ticks, with most likely to be coinfected (23.8%) and spp. and spp. as the most common combination (16.7%). The results of this study reflect high diversity and complexity of pathogens in ticks, which are useful for designing more targeted and effective control measures for tick-borne diseases in China.