Species diversity of tick and tick-borne pathogens from roe deer (Capreolus pygargus tianschanicus), including new record of Haemaphysalis megaspinosa (Acari: Ixodidae), in Jeju Island, Republic of Korea

Hard ticks (Ixodidae family) are primary vectors of zoonotic diseases, including severe fever with thrombocytopenia syndrome (SFTSV), anaplasmosis, babesiosis, Lyme borreliosis, and ehrlichiosis. The roe deer (Capreolus pygargus tianschanicus), a key host for tick-borne diseases, is widely distributed on Jeju Island, Republic of Korea (ROK). Although the increased interactions between deer, livestock, and humans have raised concerns about zoonotic disease transmission, this area has remained understudied. Therefore, this study aimed to investigate the species diversity of ticks infesting roe deer and the prevalence of major tick-borne diseases in this region. From 2018 to 2020, 1832 ticks were collected from 154 roe deer. Four tick species were identified: Haemaphysalis longicornis (50.1 %), H. flava (47.9 %), Ixodes nipponensis (1.7 %), and H. megaspinosa (0.3 %). This study reports the first detection of H. megaspinosa in the ROK. Pathogen screening detected Anaplasma spp. (minimum infection rate, MIR: 0.38 %), Babesia spp. (0.05 %), and Ehrlichia spp. (0.44 %); however, sequencing was only successful for Anaplasma spp. These findings highlight the importance of continued tick surveillance and research on the zoonotic risks associated with emerging tick species in the ROK.