Babesiosis in the immunocompromised population. Results from a multicentric cohort study conducted in Italy

Human babesiosis is an emerging zoonotic disease; diffused especially in some regions of the United States, it has been less frequently observed in other continents, including Europe. Serological surveys suggest that babesiosis could be more frequent than expected in European countries, representing an emerging health-issue and a possible harm, especially in immunocompromised populations. Only one case of human babesiosis has been reported in Italy and data about the diffusion of the pathogen in this country are scant. We conducted a multicentric serological survey in 5 centers of North-Eastern Italy, aimed to detect the seroprevalence of Babesia spp. antibodies in 3 groups of immunocompromised patients: people living with HIV (PLHIV), rheumatologic patients undergoing immunosuppressive therapies and patients undergoing renal transplant. Among the 433 enrolled patients, 3 (0.7%) tested positive for Babesia spp. serology. All positive patients belonged to the PLHIV group, with a seroprevalence of 1.7% (3/ 180) in this population; the three serologically positive patients were all asymptomatic. They were all enrolled in the provinces of Bolzano and Trento, where seroprevalences of 3.1% and 3.6% were recorded, respectively. Our results suggest that further research is needed on this field, awareness should be raised toward the human disease in Europe, especially in immunocompromised patients, and this emerging health issue should be analyzed in a One-Health perspective to be fully understood.