Natural infections of small mammals with blood parasites on the borderland of boreal and temperate forest zones

Blood parasites of small mammals living in Białowieża Forest (eastern Poland) were investigated between 1996 and 2002. The following haemoparasite species were found: Trypanosoma (Herpetosoma) evotomys in bank vole Clethrionomys glareolus and root vole Microtus oeconomus; Babesia microti in root vole; Hepatozoon erhardovae in bank vole and Hepatozoon sp. in root vole. Some non-identified Bartonella species were found in bank vole, root vole, field vole Microtus agrestis, yellow-necked mouse Apodemus flavicollis, common shrew Sorex araneus, Eurasian water shrew Neomys fodiens, and Mediterranean water shrew N. anomalus. The prevalence and diversity of blood parasites were lower in shrews than small rodents. Totally, 52.0% of bank voles, 50.0% of root voles, 32.5% of common shrews, and 41.2% of Eurasian water shrews were infected with any of the blood parasites. Mixed infections were seldom observed in bank vole (17.3% of investigated individuals) and root vole (14.7%). No animals were infected with three or four parasites simultaneously. Infection of Białowieża small mammals with haemoparasites seemed to be similar to those described in other temperate forest regions rather than boreal ones. Infection rates of rodent species seem to be higher in their typical habitats: for bank vole it was the highest in mixed forest, whereas for root vole in sedge swamp. The results suggest that Microtidae play a greater role than Muridae or Soricidae in maintenance of Babesia and Hepatozoon foci in natural environments of central Europe