(Rathke, 1862) as a vector of potentially pathogenic fungi in aquatic ecosystems.

The aim of the study was to check the integument and alimentary tract of for the occurrence of fungi. Moreover, the mycological purity of water sources from which leeches were collected was analyzed. The potential role of the duck leech in transmitting pathogenic fungi has not been studied until now. Mycological analyses were performed according to the procedure approved in mycological diagnostic laboratories, using classical diagnostic methods (macro- and microcultures, microscopic observations). In total, 22 species of yeasts were detected. The specimens belong to eight genera: , , , , , , and Overall, 18 species of fungi were isolated from leeches , including seven species from the integument and 11 species from the gastrointestinal system. Among fungi isolated from body integument, fungi of the genus were dominant, whereas in the gastrointestinal system, the genus dominated. From the river waters, nine fungi species were isolated, and yeasts of the genera and dominated. Isolation of the same species of microfungi from the integument of leeches and the river water suggests that may be a potential vector of pathogenic yeasts for vertebrates living in the same ecosystems and for humans.