Spotted fever group rickettsiae were the dominant pathogens in parasitic Rhipicephalus microplus in Yunnan Province, China*

ObjectiveTicks as ectoparasites might carry many pathogens and transmitted to their hosts through blood feeding. Human might have the opportunity to be bite by ticks, therefore getting various tick-borne pathogens. Distribution of bacterium flora in ticks plays an essential role in mapping and preventing local tick-borne diseases. Our aim is to map the distribution of bacterium flora and identify the main tick-borne pathogens in dominant tick species in grazing areas of Yunnan province. MethodsV3-V4 region of 16S rRNA amplifier sequencing was used to analyze and study the tick-borne pathogens in Rh. Microplus. The prevalence survey on B.burgdorferi s.l., B. miyamotoi, E. chaffeensis, A. phagocytophilum, Coxiella burnetii and Spotted fever group rickettsiae was carried out via PCR. ResultsThe results showed 105 genus and 117 species were detected in 50 (24 in Yunpan, 26 in Menghun) ticks. Pathogen prevalence testing showed the ticks were positive for B.burgdorferi s.l.(9/50, 18%), Spotted fever group rickettsiae (35/50, 70%), and A.phagocytophilum (1/50, 2%). ConclusionIn our analysis, Spotted fever group rickettsiae were the dominant pathogens in these areas. At the same time, we found that v3-v4 high-throughput sequencing of 16S rRNA gene is not sensitive to identify species for certain bacteria(such as B. burgdorferi s.l.). More accurate and comprehensive analysis would be necessary for detecting tick bacterium flora.