PREVALENCE OF ANTIBODIES TO BORRELIA-BURGDORFERI IN DANISH RODENTS

Six rodent species from six Danish localities were examined for antibo dies to Borrelia burgdorferi by immunofluorescence assay (IFA). A tota l of 1097 specimens were tested using a serum titre of 1:8. The wild m ice Apodemus sylvaticus and A. flavicollis had high prevalences of B. burgdorferi antibodies of 42.1% and 27.9% respectively, but the vole M icrotus agrestis also showed an exceptionally high prevalence of 32.7% . Clethrionomys glareolus had a low average prevalence of 17.4%. The l owest and highest prevalences of rodents 'seropositive for B. burgdorf eri of 6.5% and 100% were found for Micromys minutus and Mus musculus respectively. Twice as many of the Microtidae voles (M. agrestis and C . glareolus) as of the family Muridae were caught, and in Denmark the actual number of seropositive Microtidae was 1.6 times higher than for Muridae. The results indicate that in Denmark the family Microtidae s pecies plays an important role as an animal reservoir host for B. burg dorferi. The prevalence of antibodies against B. burgdorferi varied fr om locality to locality, but seropositive rodents were found at all lo calities examined, indicating that the spirochete was widely present i n Denmark.