Anti-Babesia microti antibodies in foresters highly exposed to tick bites in Poland

Abstract

Human babesiosis caused by Babesia microti and Babesia divergens parasites is an emerging tick-borne disease worldwide. The prevalence of infection and frequency of the disease caused by B. microti in Europe is not well known. The aim of our study was to evaluate the frequency of anti-B. microti antibodies in the serum of forest employees (a population highly exposed to tick bites) from 2 different regions of Poland. We studied 114 foresters from 2 separate forest inspectorates in north-eastern and central Poland. Direct immunofluorescence assays (Babesia microti IgM and IgG IFA kits) were used to detect serum IgM and IgG anti-B. microti antibodies. Simultaneously, anti-B. burgdorferi antibodies were detected using an enzyme-linked immunosorbent assay kit, and positive cases were confirmed with immunoblot. Anti-B. microti IgG antibodies were detected in 5 foresters (4.4%), all from the forest inspectorate in Białowieża in the northeast of the country. All persons with anti-B. microti antibodies were also IgG-seropositive for B. burgdorferi. Our results suggest that unrecognized infections with B. microti occur in the Polish population and should be considered in the differential diagnosis of a febrile illness occurring after exposure to ticks, particularly in patients from endemic regions.