Micromammals as a reservoir for the zoonotic nematode Calodium hepaticum (syn. Capillaria hepatica) in recreational areas of Slovakia

The hepatic nematode Calodium hepaticum is a zoonotic parasite primarily parasitising small mammals, but it can infect a wide range of mammal species, including humans. Due to its specific life cycle and transmission pattern, it is one of the least studied helminths in the world. The only documented findings of C. hepaticum from Slovakia (former Czechoslovakia) come from the 60s and 70s of the 20th Century, including nine human cases of the infection reported post-mortem. The present study was conducted in the area of these original records in the Tatra National Park (TANAP) and the Košice Zoo. In TANAP, 484 small mammals of six shrew species (Insectivora: Soricidae) and eight rodent species (Rodentia: Muroidea) were collected. In the Košice Zoo, 163 rodents from 10 species were sampled. All specimens were examined for the presence of C. hepaticum eggs using the artificial digestion method. The parasite was recorded in two shrew species (Sorex araneus and Neomys fodiens) and five rodent species (Arvicola amphibius, Microtus agrestis, Clethrionomys glareolus, Apodemus flavicollis, and Rattus norvegicus) from TANAP, while in the Košice Zoo only a single individual of R. norvegicus was found to be infected. [Display omitted] •A total of 647 small mammals of 16 species were examined during 2018–2023 in Slovakia.•Calodium hepaticum was detected in multiple species of shrews and rodents in the Tatra National Park.•Only one rodent individual was infected in the Košice Zoo.•The study suggests a persistent focus of C. hepaticum in the Tatra National Park.•The results highlight the need to monitor synanthropic rodents for infections with this nematode.