A historical review of Babesia spp. associated with deer in Europe: Babesia divergens/Babesia divergens-like, Babesia capreoli, Babesia venatorum, Babesia cf. odocoilei

This review is intended to provide an overview of the occurrence and diversity of Babesia spp. in European deer. Babesiosis is an emerging vector-borne disease with negative implications on animal and public health. Cervidae are important hosts for Ixodidae ticks, playing a critical role in the epidemiology of the parasite. Deer are susceptible to different Babesia spp., some of them with zoonotic potential. The infection is usually asymptomatic with high prevalence rates, although some fatal cases due to B. capreoli and B. venatorum have been reported. In Europe, 3 main Babesia spp. have been described in deer: Babesia divergens/B. divergens-like, B. capreoli and B. venatorum. Additionally, close relatives of B. odocoilei, the Babesia species of the American white-tailed deer (Odocoileus virginianus), have been isolated in several European countries. The occurrence of B. divergens/B. divergens-like generated concerns about the role of cervidae in the life cycle of the parasite, and the potential threat for public health. Few human cases have been attributed to B. venatorum so far, including hunters. Although this species is strictly related to the presence of roe deer (Capreolus capreolus), it has been occasionally reported in moose (Alces alces) and captive reindeer (Rangifer tarandus). Over recent years, vector-borne diseases received increased attention from International Organizations. However, technical difficulties persist, affecting surveillance efficiency. Given the veterinary and zoonotic importance of babesiosis, the author advocates the need for an effective monitoring at wildlife-domestic animals-humans interface and the implementation of management plans to reduce the risk of Babesia spp. infection for both humans and domestic animals.