Hidden highways: fungi associated with glossiphoniid leeches

Fungi associated with aquatic invertebrates remain poorly characterized, particularly those inhabiting leeches (Hirudinea), which are key components of freshwater ecosystems. In this study, the fungal communities associated with five species of glossiphoniid leeches were investigated, and isolates were obtained and compared from internal tissues and the body surface. In total, 19 fungal species were identified, including plant pathogens (e.g., Cadophora luteo-olivacea, Comoclathris typhicola, Plectosphaerella plurivora) and opportunistic human pathogens (e.g., Meyerozyma guilliermondii, Mucor circinelloides, Arthroderma sp.). Notably, Papiliotrema aurea, a fungus known to infect invertebrate tissues, was detected inside Glossiphonia complanata. The occurrence of several taxa both in the surrounding water and on leeches suggests that leeches may act as vectors of fungal dispersal in aquatic ecosystems. The results highlight the importance of leeches not only as potential dispersal agents of plant pathogens, which may affect vegetation and aquaculture, but also as reservoirs of opportunistic human pathogens.