Genetic diversity of spotted fever group Rickettsia and Dabieshan tick virus detected in ticks collected from suburban forest areas of Gifu, Central Japan.

This study investigated the prevalence and genetic diversity of tick-borne pathogens in the forested suburbs of Gifu in central Japan, where human cases of Japanese spotted fever and severe fever with thrombocytopenia syndrome (SFTS) have recently been reported. A total of 130 ticks representing eight species were analyzed for spotted fever group Rickettsia (SFGR) and viruses in the family Phenuiviridae using PCR and reverse transcription-PCR, respectively. While the causative agents of Japanese spotted fever (Rickettsia japonica) and SFTS were not detected in this study, SFGR-specific genes were identified in 35 specimens. Candidatus Rickettsia jingxinensis was the predominant species, primarily associated with Haemaphysalis longicornis ticks. Multiple lineages related to Rickettsia monacensis and other uncharacterized species were also identified, reflecting a highly diverse rickettsial population. Dabieshan tick virus (DTV), a member of the family Phenuiviridae, was detected in 11H. longicornis specimens, marking its first identification in central Japan. Notably, these strains form a genetically unique clade distinct from previously detected DTV strains in Japan. Although the pathogenicity of the microorganisms detected in this study remains unclear, our findings highlight the diversity of tick-borne microorganisms in this area. The substantial diversity, characterized by multiple rickettsial lineages and the presence of a unique DTV clade, underscores the importance of continuous surveillance to understand this complex microbial landscape and its potential implications for public health.