Molecular Detection of () and Spp. in Hard Ticks Distributed in Tokachi District, Eastern Hokkaido, Japan

Ticks transmit various pathogens, including parasites, bacteria and viruses to humans and animals. To investigate the ticks and the potentially zoonotic pathogens that they may carry, questing ticks were collected in 2017 from 7 sites in Tokachi District, eastern Hokkaido, Japan. A total of 1563 ticks including adults (male and female), nymphs and larvae were collected. Four species of ticks were identified: , , and . Of the 1563 ticks, 1155 were used for DNA extraction. In total, 527 individual tick DNA samples prepared from adults ( = 484), nymphs ( = 41) and larvae ( = 2); and 67 pooled tick DNA samples prepared from larval stages ( = 628) were examined using PCR methods and sequencing to detect () and spp. The phylogenetic analysis of spp. gene sequences showed the presence of the human pathogenic () species (, and ) in . , whereas the non-pathogenic species was found only in . In . , and/or its closely related species was detected in both adults and nymphs at a prevalence of 21.9% whereas was found only in adults (1.8%). The prevalence of in adult . was 21.8%. species were identified through phylogenetic analysis based on , 16S rRNA, and genes. Four genotypes were detected in the samples which were classified into three species. The prevalence of human pathogenic was 26.0% in adults and nymphs, 55.6% in larval pools, and 1.7% in larval pools. The prevalence of " R. tarasevichiae" was 15.4% in adults and nymphs and 33.3% in larval pools. The prevalence of " R. principis" in adults and nymphs was 11.1% whereas it was detected in 3.4% of the larval pools. These results indicate that most of the risks of Lyme borreliosis and spotted fever group rickettsiosis infection in eastern Hokkaido, Japan, are restricted to .