Babesiosis is a tick-borne disease caused by intraerythrocytic protozoa belonging to the genus Babesia that is primarily transmitted through Ixodid ticks and is highly pathogenic to ruminants, horses, pigs, dogs, cats, and in some cases, even humans. Babesia is considered an increasing threat to animal and human health. In this study we report Babesia capreoli infection in Korean water deer (Hydropotes inermis argyropus). Blood samples of 77 wild animals (62 Korean water deer and 15 Korean raccoon dogs [Nyctereutes procyonoides koreensis]) were analyzed to detect Babesia infection. First, PCR was performed to investigate Babesia infection using the partial 18S rRNA gene. Among the 77 wild animals examined, 11 Korean water deer were positive for infection as per the results of sequence analysis. Next, these 11 samples were reanalyzed by PCR using newly designed primers to differentiate between B. capreoli and Babesia divergens. Finally, only one Korean water deer sample was found to be positive for B. capreoli. The nucleotide sequence of this protozoan showed 99.6 - 99.7% identity to those of B. capreoli reported previously. Phylogenetic analysis revealed that the sequence belonged to the B. capreoli clade and diverged from the B. divergens clade. Three nucleotides at positions 631, 663, and 1637 were analyzed to differentiate between B. capreoli and B. divergens. The nucleotides at positions 631 and 1637 were identical to those of B. capreoli, whereas that at position 663 was different. The sequence detected in Korean water deer also exhibited differences at other four positions (669, 704, 711, and 1661) compared with other B. capreoli sequences. This study indicates that Korean water deer serve as a reservoir for B. capreoli. In addition, the primers designed in this study can be used to detect B. capreoli. Future studies should explore the tick vectors that transmit B. capreoli and its pathogenicity. This study was approved by the Institutional Committee of Graduate Studies and Research at Jeonbuk National University, ROK (IACUC decision no.: CBU 2014-00026).
Keywords: Babesia capreoli; Korean water deer; reservoir; tick.