Detection of severe fever with thrombocytopenia syndrome (SFTS) virus from wild ticks collected in Kagoshima Prefecture, Japan

Ticks are important vectors of pathogens that cause serious diseases such as Lyme disease, Japanese spotted fever, and severe fever with thrombocytopenia syndrome (SFTS). For effective control of tick-borne diseases, it is important to know the distribution of ticks and pathogens within the endemic area. This study aims to investigate the tick fauna and virus infection rates in ticks in the endemic area. In Kagoshima Prefecture, where SFTS is endemic, ticks were collected in April and October of 2013 from 15 fixed points in a mountain forest area (20 km2 area) on the Osumi Peninsula. The collected ticks were identified to species through genetic analysis, and the detection of SFTS virus was confirmed through RT-PCR. The results showed that SFTS virus genes were detected in four tick species: Haemaphysalis formosensis, H. longicornis, H. hystricis and H. flava. The SFTS virus gene was detected in all stages of tick development (larvae, nymphs, and adults), and in 7.1% (April) and 5.8% (October) of the total number of ticks in the area. In ticks collected in autumn, the SFTS virus gene was also detected in unfed larvae after hatching, indicating possible vertical (transovarial) transmission via eggs.