Molecular identification of cestodes from rodents in the Mazury Lake District region of Poland

Rodents serve as hosts for many species of parasites, including cestodes, but the taxonomy of rodent-infecting tapeworms, especially in Central Europe, is still understudied. Therefore, the current study was conducted to identify larval and adult cestodes in free-living rodents from Northeastern Poland. The fieldwork was conducted between 2014 and 2023 in three forest sites. Cestodes were collected from five rodent species (Clethrionomys glareolus, Alexandromys oeconomus, Microtus agrestis, Apodemus agrarius and A. flavicollis, and were identified through morphology and by several genetic markers (12S rDNA, cox1, nad 1, 28S rDNA, 12S-16S rDNA) using phylogenetic analyses. A total of 58 cestode specimens were analyzed using molecular and phylogenetic analyses. Species identified included Catenotaenia henttoneni, Spasskijela kratochvili, Mesocestoides litteratus, Mesocestoides melesi, and others. Three Paranoplocephala specimens were identified as P. kalelai based on nad1 sequences. Morphological and genetic analyses indicated that the dominant adult cestode in bank vole was C. henttoneni and Mesocestoides spp. were the dominant larval cestodes. This study combined genetic and morphological methods to identify the cestodes infecting rodents in Poland. It confirmed the existence of P. kalelai in Poland, suggesting that previously reported Paranoplocephala spp., identified by morphological characters, may have corresponded to this molecularly identified species. Our study also highlighted gaps in genetic databases that currently still do not allow precise species identification.