E-coli O157:H7 in water:: a public health problem.

Waterborne E. coli O157:H7 illness can occur as a result of contamination of the source water, treatment failure or post-treatment contamination. Recreational water, private and municipal supplies have been implicated from microbiological environmental and epidemiological studies. Sources of contamination are thought to be animal and human faeces or sewage. The use of contaminated water for irrigating, spraying or washing food items to be eaten raw may be a risk. However waterborne infection is relatively rare and properly disinfected and protected.