The emergence of tick-borne viral diseases has significantly led to intensified efforts to identify viruses harbored by ticks. In this study, we employed next-generation sequencing to analyze RNA viral sequences present in 1360 questing ticks collected from the Ishikawa and Ehime Prefectures, Japan. Phylogenetic analysis of these viral sequences suggested that these viruses may not be affiliated with vertebrate-infecting groups but instead, show close relationships with previously reported tick-specific viruses. A novel iflavirus has been detected in Ixodes turdus tentatively named Ixodes turdus iflavirus, displaying less than 52% similarity to the amino acid sequence of its closest known virus. Two new strains of Hubei tick virus 3 belonging to the Iflaviridae family, were detected in Haemaphysalis formosensis. Furthermore, Ehime tick reovirus (EhTRV), identified in Haemaphysalis flava, shares approximately 89% pairwise amino acid identity of the largest polymerase protein with Zoersel tick virus, suggesting a close relationship. Lastly, two different segments of an unclassified sobemo-like virus were identified as putative novel species. The findings of this study offer new insights into the presence of viruses in questing ticks, particularly in specific regions of 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.

Recently, a growing concern has been observed regarding the increasing incidences of tick-borne infectious diseases and expansion of the endemic areas in multiple locations worldwide. In the Japan Sea coast area of Tohoku region, the establishment of wild boar over several years, alongside potential increases in the Japanese black bear, have raised concerns about tick community change. However, data on tick infestations of wildlife in this area remain limited. Therefore, this study explored tick infestations on newly established wild boar and indigenous Japanese black bears in the area, with ticks collected from one wild boar and three Japanese black bears captured for agricultural and human health protection in Tsuruoka City, Yamagata Prefecture. Results revealed adult Amblyomma testudinarium infesting wild boar as well as several adult Dermacentor bellulus infesting wild boar and Japanese black bears. Dermacentor bellulus was the predominant tick species on both host species in the current study. These findings highlight the role of newly established wild boar and indigenous Japanese black bears as hosts of southern tick species in the Japan Sea coast area of Tohoku region. Further research is necessary to determine contemporary changes in tick community and the associated risks of tick-borne diseases this area.

Ixodid ticks were surveyed in western Tottori and eastern Shimane Prefectures in 2013–2014 using the flannel method. Seven species were collected in western Tottori Prefecture. Among them, Ixodes tanuki is newly record from Tottori Prefecture. The record of Haemaphysalis hystricis in this survey is the oldest collection record of H. hystricis in Tottori Prefecture. Nine species of ticks were collected in eastern Shimane Prefecture. When surveys were conducted in Yonago City, western Tottori Prefecture, and Yasugi City, eastern Shimane Prefecture, on almost the same survey dates and with the same effort in 2014, significantly higher numbers of individual of H. hystricis were collected in Yasugi City than in Yonago City.

This study reports the results of our examination of the history of the cockroach index and its spread in Japan. Internet information has revealed that the cockroach index was not proposed in 1991, as previously believed, but rather in 1962. In addition, we clarify that the cockroach index has been widely used in the management of building environments and sanitation since the late 1980s.

We describe a case of human tick infestation by an adult male specimen of Dermacentor bellulus. The tick was found on the skin of the right upper arm in a 6-year-old Japanese male, who had visited around Nagasawa, Yatsuo-cho, Toyama City, Honshu, Japan. The tick was identified as an adult male of D. bellulus based on its morphological characteristics. This is the first case of human infestation by D. bellulus accompanied by patient information.