Int. J. Environ. Res. Public Health 2010, 7, 3225-3234; doi:10.3390/ijerph7083225 OPEN ACCESS International Journal of Environmental Research and Public Health ISSN 1660-4601 www.mdpi.com/journal/ijerph Article Microfungi in Drinking Water: The Role of the Frog Litoria caerulea Noel B. Sammon 1,*, Keith M. Harrower 1, Larelle D. Fabbro 2 and Rob H. Reed 1 1 2 Centre for Plant and Water Science, CQUniversity Australia, Bruce Highway, Rockhampton, Queensland, Australia 4702; E-Mail: r.reed@cqu.edu.au (R.H.R.) Centre for Environmental Management, CQUniversity Australia, Bruce Highway, Rockhampton, Queensland, Australia 4702; E-Mail: l.fabbro@cqu.edu.au (L.D.F.) * Author to whom correspondence should be addressed; E-Mail n.sammon@cqu.edu.au; Tel.: +61-7-4930-9556; Fax: +61-7-4930-9255. Received: 20 July 2010; in revised form: 9 August 2010 / Accepted: 16 August 2010 / Published: 19 August 2010 Abstract: Microfungi were recovered from all parts of a municipal water distribution system in sub-tropical Australia even though virtually no colony-forming units were recovered from the treated water as it left the treatment plant. A study was then undertaken to determine the potential sources of the microfungal population in the distribution system. Observation of frogs (Litoria caerulea) using the internal infrastructure of a reservoir as diurnal sleeping places, together with observation of visible microfungal growth on their faecal pellets, led to an investigation of the possible involvement of this animal. Old faecal pellets were collected and sporulating fungal colonies growing on their surfaces were identified. Fresh faecal pellets were collected and analysed for microfungal content, and skin swabs were analysed for yeasts. It was found that the faeces and skin of L. caerulea carried large numbers of yeasts as well as spores of various filamentous fungal genera. While there are many possible sources of microfungal contamination of municipal drinking water supplies, this study has revealed that the Australian green tree frog L. caerulea is one of the important sources of filamentous microfungi and yeasts in water storage reservoirs in sub-tropical Australia where the animal is endemic. Keywords: filamentous fungi; yeasts/yeast-like; Australia