[Surveillance of Tick Populations in the Republic of Korea in 2024].

OBJECTIVES

Hard ticks are major vectors carrying various pathogens in the Republic of Korea (ROK), including the severe fever with thrombocytopenia syndrome (SFTS) virus. Recent findings suggest ticks have the potential to carry multiple infectious agents. We assessed hard tick distribution to improve tick-borne disease risk assessment by providing up-to-date information regarding tick density and pathogen presence.

METHODS

From April to November 2024, ticks were collected monthly from 16 sites spanning four high-risk environments (mountain roads, graves, copses, and grasslands). Twelve traps (three per environment) baited with dry ice were placed at each site. Tick density was measured using the average number of ticks collected per trap for comparison with previous years.

RESULTS

In total, 71,924 hard ticks representing three genera and six species were collected. Haemaphysalis longicornis, the primary vector of SFTS, accounted for 97.3% of the identified ticks (excluding larvae). The overall hard tick index in 2024 was 46.8, with the highest levels observed in August and September and the lowest levels in October and November.

CONCLUSIONS

The 2024 hard tick index was 46.8, representing a 30.0% increase over 2023 (36.0) and a 13.9% increase over the 2020 to 2022 average (41.1). The increase in the hard tick index is presumed to be due to the rise in average temperature and a sharp increase in tick density in certain regions. As the risk of vector-borne diseases increases due to climate change in ROK, it is essential to adhere to prevention guidelines to avoid infectious diseases.