Serbia reports first Borrelia records in voles and Apodemus mice

A newly reported Serbian study has identified Borrelia burgdorferi sensu lato in voles and selected Apodemus mice for the first time, with Borrelia afzelii specifically detected in the sampled animals. That makes the paper less about a surprise pathogen arrival than about a clearer view of the wildlife reservoir network supporting Lyme borreliosis ecology in Serbia. (lmaleidykla.lt)

The background matters here. Serbia has documented Lyme-related Borrelia circulation for years, including detections in Ixodes ricinus ticks, earlier isolation from Apodemus flavicollis in the Belgrade area, and later work showing multiple Borrelia genospecies in ticks from different Serbian localities. Human Lyme borreliosis has also been recognized in Serbia since the late 1980s. What this new report adds is host-level evidence in vole and selected Apodemus species that had not previously been recorded in the country in this way. (pubmed.ncbi.nlm.nih.gov)

That distinction is important because B. afzelii is widely regarded as a rodent-associated member of the B. burgdorferi sensu lato complex in Europe. Reviews and prior ecological studies consistently describe Apodemus mice and vole species as key participants in rodent-tick maintenance cycles, even though the reservoir competence of individual species can vary by place, pathogen strain, and habitat. Recent literature reviewing European Apodemus species also points to repeated associations between these mice and Borrelia, especially B. afzelii. (pmc.ncbi.nlm.nih.gov)

The Serbian findings also fit with more recent local surveillance. A 2024 retrospective study of small mammals from Serbia reported first findings of several tick-borne pathogens in those hosts, including B. afzelii in Apodemus flavicollis, and called for larger contemporary studies to define the epidemiologic role of particular small mammal species more clearly. Separately, Serbian tick studies have found substantial Borrelia diversity, including B. afzelii, B. garinii, B. lusitaniae, B. valaisiana, and B. bavariensis, reinforcing that the pathogen landscape is broader than a single species or host. (journals.sagepub.com)

Direct expert reaction to this specific paper was limited in publicly indexed coverage, but the broader scientific commentary is fairly consistent: small mammals are central to enzootic maintenance of Lyme-group spirochetes, and local host data matter because transmission ecology is highly regional. That means a “first record” paper can be operationally useful even when it doesn’t immediately change clinical practice. It helps define where pathogen maintenance is occurring, which host species are involved, and where future tick and wildlife surveillance should be concentrated. This is an inference drawn from the surrounding literature and Serbian surveillance record. (pmc.ncbi.nlm.nih.gov)

Why it matters: For veterinary professionals, the practical takeaway is surveillance, not alarm. Companion animal clinicians in Serbia and neighboring markets already know ticks carry multiple pathogens, but reservoir-host studies add granularity to that risk picture. If voles and Apodemus mice are helping maintain B. afzelii locally, that supports stronger seasonal tick-control counseling, more informed discussions with pet parents about exposure in peri-urban and rural habitats, and closer coordination between veterinary, wildlife, and public health surveillance teams. It also reinforces the value of considering co-circulating tick-borne pathogens rather than thinking about Lyme borreliosis in isolation. (journals.sagepub.com)

There are still limits to what this study can tell us. Detection in wildlife hosts does not by itself establish the full reservoir competence, transmission efficiency, or geographic spread of infection. Prevalence can vary sharply by species, season, habitat, and sampling design, and the Serbian literature itself has called for larger, prospective, contemporary field studies. (journals.sagepub.com)

What to watch: The next meaningful step will be integrated rodent-tick surveillance across more Serbian regions, ideally pairing host testing with tick genotyping and habitat data. If those studies confirm stable rodent maintenance cycles for B. afzelii or identify additional Borrelia genospecies in the same hosts, that could improve veterinary risk communication and regional One Health mapping. (journals.sagepub.com)