Abstract

As microbial contamination of leeches poses a risk of transmission of pathogens to humans, contact with non-sterile leeches causes a potential hazard to human health. The purpose of this study was to evaluate the mycological purity of the body surface, jaws/pharynx and intestines of the medical leech, Hirudo verbana, and the purity of aquarium water within which the leeches were incubated. Leeches were kept without feeding under optimum laboratory conditions recommended for medicinal uses. The strains of fungi were isolated according to our own methods and standard mycological procedures. Of the 150 cultures taken from 50 leeches and 50 samples of water, 152 strains of yeast-like fungi and yeasts belonging to 14 species and 3 genera were identified. The greatest number of fungal species (11) was isolated from the leech jaws, next (10) from the body surface, while the fewest species (8) were found from the samples of water in which the animals were maintained. Fungal isolates belonging to biosafety level two (BSL-2), classified as potential pathogens for humans identified were Candida albicans, Candida ciferrii, Candida krusei, Candida tropicalis, Trichosporon asahii and Trichosporon asteroides. Some other isolates with a decreased pathogenicity potential (BSL-1) also identified were Candida guilliermondii, Candida famata, Candida lambica, Candida parapsilosis and Rhodotorula rubra. The isolation of a high number of yeast-like fungal strains from H. verbana suggests that this medical leech is a vector of potentially pathogenic human fungal species.

Key words: Yeast-like fungi, Candida spp., leeches, Hirudo verbana, vector.