Seroprevalence of Toxoplasma gondii among Sylvatic Rodents in Poland

SIMPLE SUMMARY: Toxoplasma gondii is a significant pathogen affecting humans and animals. Rodents are known to be reservoir hosts of T. gondii and therefore play a significant role in the dissemination of this parasite. We conducted seromonitoring for T. gondii in four sylvatic rodent species in Poland. We report an overall seroprevalence of 5.5% (3.6% for Myodes glareolus and 20% for other vole species). Seroprevalence in bank voles varied significantly between host age and sex. Our results, therefore, make a significant contribution to the understanding of the role of wild rodent populations in the maintenance and dissemination of T. gondii and identify key factors that affect the magnitude of seroprevalence in specific host populations. ABSTRACT: Toxoplasma gondii is an intracellular Apicomplexan parasite with a broad range of intermediate hosts, including humans and rodents. Rodents are considered to be reservoirs of infection for their predators, including cats, felids, pigs, and wild boars. We conducted a multi-site, long-term study on T. gondii in northeastern Poland. The study aimed to monitor the seroprevalence of T. gondii in the four abundant vole species found in the region (Myodes glareolus, Microtus arvalis, Microtus agrestis, and Alexandromys oeconomus) and to assess the influence of both extrinsic (year of study and study site) and intrinsic (host sex and host age) factors on seroprevalence. A bespoke enzyme-linked immunosorbent assay was used to detect antibodies against T. gondii. We examined 577 rodent individuals and detected T. gondii antibodies in the sera of all four rodent species with an overall seroprevalence of 5.5% [4.2–7.3] (3.6% [2.6–4.9] for M. glareolus and 20% [12–30.9] for M. arvalis, M. agrestis, and A. oeconomus). Seroprevalence in bank voles varied significantly between host age and sex. Seroprevalence increased with host age and was higher in females than males. These results contribute to our understanding of the distribution and abundance of T. gondii in voles in Poland and confirm that T. gondii also circulates in M. glareolus and M. arvalis, M. agrestis and A. oeconomus. Therefore, they may potentially play a role as reservoirs of this parasite in the sylvatic environment.