Waterborne cryptosporidiosis.

Awareness of the importance of Cryptosporidium as a gastrointestinal parasite of developed countries not only stems from its prevalence in AIDS patients but also from its recent recognition as a possible contaminant of drinking water supplies. The importance of Cryptosporidium to public health has recently been revealed by a series of major epidemics of diarrhoeal disease in the USA and UK. In this review, Huw Smith and Joan Rose document what is known of the causes of some of these outbreaks and explain why this parasite can escape the battery of treatment processes normally used for drinking water supplies in these countries.