Detection of rickettsial DNA in ticks and wild boars in Kyoto City, Japan

The tick is a well-known vector for arthropod-borne pathogens, such as tick-borne encephalitis, Lyme disease, Japanese spotted fever and severe fever with thrombocytopenia syndrome. It is therefore important to know the tick population and distribution in our environment and wild animals in order to prevent tick-borne diseases. Here, we report the results of tick surveillance from May to September 2011 at 14 geographical points and in 5 wild boars in Kyoto City, Kyoto prefecture, Japan. We collected 3,198 ticks comprising 5 tick species, Haemaphysalis (H.) longicornis, H. flava, H. kitaokai, Amblyomma testudinarium and Dermacentor taiwanensis. Interestingly, the proportion of tick species varied according to geographical region within the city. The ticks collected in the city were reported as potential vectors of pathogens, such as rickettsiosis. We detected rickettsial DNA by PCR in 71.1% of 201 ticks investigated. The ticks that carried rickettsiae were distributed across the whole the city. The sequences of PCR-amplified DNA fragments were determined and showed similarities to spotted fever group rickettsiae. Although their pathogenicity for animals including humans is still unclear, it is important to stay alert and pay attention to tick-borne diseases in order to ensure the safety of the citizens of the city as well as that of visitors.