Molecular identification of species in recreational waters in North-Eastern Poland.

BACKGROUND

In Europe, avian schistosomes of the genus are the most common etiological agents involved in human cercarial dermatitis (swimmer's itch). Manifested by a skin rash, the condition is caused by an allergic reaction to cercariae of nonhuman schistosomes. Humans are an accidental host in this parasite's life cycle, while water snails are the intermediate, and waterfowl are the final hosts. The study aimed to conduct a molecular and phylogenetic analysis of species occurring in recreational waters in North-Eastern Poland.

METHODOLOGY

The study area covered three water bodies (Lake Skanda, Lake Ukiel, and Lake Tyrsko) over the summer of 2021. In total, 747 pulmonate freshwater snails ( spp) were collected. Each snail was subjected to 1-2 h of light stimulation to induce cercarial expulsion. The phylogenetic analyses of furcocercariae were based on the partial sequence of the ITS region (ITS1, 5.8S rDNA, ITS2 and 28SrDNA). For spp. phylogenetic analyses were based on the ITS-2 region.

RESULTS

The prevalence of the species infection in snails was 0.5%. Two out of 478 (0.4%) were found to be infected with Moreover, two out of 269 (0.7%) snails of the genus were positive for schistosome cercariae. Both snails were identified as . One of them was infected with and the other with sp.

CONCLUSIONS

Molecular identification of avian schistosome species, both at the intermediate and definitive hosts level, constitutes an important source of information on a potential threat and prognosis of local swimmer's itch occurrence, and helps to determine species diversity in a particular area.