Guidelines for Canadian recreational water quality: Microbiological pathogens and biological hazards: Pathogenic microorganisms

Numerous pathogenic microorganisms can potentially be found in recreational environments. The three main types are bacteria, viruses and protozoa. Many occur as a result of contamination from human or animal wastes, whereas some are free-living microorganisms that exist naturally in the recreational water environment. A fourth type that may be of concern at some beaches, particularly associated with beach sand, are fungi.