Sika Deer Carrying Babesia Parasites Closely Related to B. divergens, Japan

To the Editor: Human babesiosis caused by Babesia divergens, a zoonotic pathogen of bovines in Europe, is an emerging tickborne disease (1). In the United States, a closely related Babesia sp. was identified in persons in Missouri and Kentucky and in eastern cottontail rabbits (Sylvilagus floridanus) on Nantucket Island, Massachusetts (2–5). We report that sika deer (Cervus nippon) in Japan also carry parasites genetically closely related to B. divergens.