Differences in the ecology of Bartonella infections of Apodemus flavicollis and Myodes glareolus in a boreal forest.

The epidemiology of Bartonella species infecting Apodemus flavicollis and Myodes glareolus in a forest in Eastern Poland was followed for 2 years using mark-recapture. Infections could be acquired in any month, but prevalence, and probability of infection, peaked in the summer. There were significant differences in the pattern of infections between the two species. Both hosts were primarily infected as juveniles, but the probability of infection was highest for A. flavicollis, which, evidence suggests, experienced longer-lasting infections with a wider range of Bartonella genotypes. There was no evidence of increased host mortality associated with Bartonella, although the infection did affect the probability of recapture. Animals could become re-infected, generally by different Bartonella genotypes. Several longer lasting, poorly resolved infections of A. flavicollis involved more than 1 genotype, and may have resulted from sequential infections. Of 22 Bartonella gltA genotypes collected, only 2 (both B. grahamii) were shared between mice and voles; all others were specific either to A. flavicollis or to M. glareolus, and had their nearest relatives infecting Microtus species in neighbouring fields. This heterogeneity in the patterns of Bartonella infections in wild rodents emphasizes the need to consider variation between both, host species and Bartonella genotypes in ecological and epidemiological studies.