First Molecular Detection of Orthohantaviruses (Orthohantavirus hantanense and O. jejuense) in Trombiculid Mites from Wild Rodents in the Republic of Korea

Orthohantaviruses are zoonotic pathogens that cause severe diseases in humans primarily through inhalation of aerosols from rodent excreta. Recent studies suggest that ectoparasites may be potential vectors for Orthohantaviruses. This study aimed to obtain molecular evidence of Orthohantavirus in trombiculid mites collected from wild rodents. In April 2025, 4963 trombiculid mites were collected from 128 wild rodents captured in 17 regions of the Republic of Korea (ROK). Among them, 1660 mites were grouped into 204 pools by collection sites and tested for the Orthohantavirus RNA using quantitative real-time polymerase chain reaction (PCR) and reverse transcription-nested PCR. OrthoHantavirus RNA was detected in seven trombiculid mite pools, with a minimum infection rate of 0.4/100 mites. <i>Orthohantavirus hantanense</i> was identified in trombiculid mites from Cheongju, Gimcheon, and Yeongdeok, while <i>O. jejuense</i> was identified in trombiculid mites from Boryeong and Jeongeup. Notably, Orthohantaviruses were not detected in the host rodents of the Orthohantavirus-positive trombiculid mites from Cheongju, Jeongeup, and Gimcheon, indicating host-independent infection. This study is the first to report detection of Orthohantaviruses, <i>O. hantanense</i> and <i>O. jejuense</i>, from trombiculid mites in the ROK. The host-independent infection suggests that these mites could serve as independent vectors/reservoirs for Orthohantaviruses, distinct from previously known transmission routes.