Current status of Trypanosoma grosi and Babesia microti in small mammals in the Republic of Korea

Abstract Background: Small mammals are natural reservoir hosts of zoonotic diseases, including parasitic protozoa. To assess the risk of rodent borne parasitic protozoa in the Republic of Korea (ROK), this study investigated the status of parasitic protozoa, namely Trypanosoma, Babesia, and Theileria in small mammals. Methods: Small mammals were captured during the spring and autumn at 16 sites. In total, 331 blood samples from small mammals were analyzed for the presence of parasites using PCR. Results: Samples were positive for Trypanosoma grosi (23.9 %; n=79) and Babesia microti (10 %; n=33). However, Theileria was not detected. The small mammals collected from Seogwipo showed the highest infection rate of T. grosi (48.4 %), while the highest B. micrtoti infection rate was observed in small mammals collected from Gangneung (25.6 %). Sequence data of T. grosi from small mammals revealed that it belonged to the T. grosi AKHA strain. Phylogenetic analysis of B. microti revealed two genotypes: the US and Kobe types. B. microti US-type-infected small mammals were detected throughout the country, but the Kobe type was only detected in Seogwipo. Conclusions: To the best of our knowledge, this is the first nationwide survey to confirm T. grosi and B. microti infections at the species level in small mammals in the ROK and the first study to identify the Kobe type of B. microti. These results provide useful information for further molecular epidemiological studies on these parasites.