Genetic variation of chigger mites in the Republic of Korea

The chigger mite is a known vector for the zoonotic disease, Tsutsugamushi, which affects more than 4,000 patients each year in the Republic of Korea (ROK) since 2004. However, molecular data is only available for a few species of chigger mite, compared to the numbers of known species. This study focused on securing molecular data for six species (Leptotrombidium pallidum, Leptotrombidium scutellare, Leptotrombidium palpale, Leptotrombidium orientale, Neotrombicula gardellai, and Eushoengastia koreaensis) of chigger mites in the ROK from cytochrome c oxidase subunit I (COI) and internal transcribed spacer 2 (ITS2). In the results, there were each two genotypes in L. pallidum and L. palpale, and three genotypes in L. scutellae in the COI, whereas the ITS2 sequence was identical within the species. The other three species were identical from COI and ITS2. This study first revealed the genetic variation in the COI sequences of chigger mites in the ROK. Further studies could determine how this variation is related to ecological behavior and disease transmission.