Kiyoon Kim, Chungbuk National University

This study investigated the species composition of parasitic ticks and the prevalence of tick-borne pathogens (TBPs) in reintroduced Asiatic black bears in South Korea, while assessing the subsequent physiological impact on the host. A total of 367 ticks were collected from 14 bears. Morphological identification identified five species, with Haemaphysalis flava (59%) being dominant, followed by Amblyomma testudinarium (14%), Haemaphysalis longicornis (23%), Haemaphysalis japonica (2%), and Ixodes nipponensis (2%). The presence of A. testudinarium, a species typically associated with large mammals, reflects the bears’ utilization of interior forest habitats where such tick species are established. Molecular screening of 71 tick pools revealed a 38% (n=27) prevalence of Rickettsia spp., while SFTSV and Borrelia spp. were not detected. Pathogen prevalence peaked in the adult stage, suggesting a pattern of bio-accumulation throughout the tick life cycle. Crucially, bears infested with Rickettsia-positive ticks (n=9) exhibited significantly higher levels of White Blood Cell (WBC) counts, Eosinophils, and Mean Corpuscular Volume (MCV) compared to the negative group (p < 0.05). These hematological alterations are associated with systemic inflammatory responses in the host. As the first comprehensive surveillance of the bear–tick–pathogen tripartite relationship in South Korea, this study highlights the importance of incorporating vector surveillance and management into wildlife conservation strategies under a One Health framework. However, further studies with larger sample sizes are required to validate these findings.