Cryptosporidium

Cryptosporidium is a microscopic, single celled parasite, which if swallowed can cause diarrhoea in animals and humans. Over the past ten years the public health significance of crytosporidium in water supplies has become much clearer, with several major outbreaks of waterborne crytosporidiosis being characterised, particularly in the UK and the USA. The cysts are normally removed by sand filtration, but this cannot be guaranteed and they are highly resistant to chlorine so that normal disinfection methods are unlikely to kill the organisms.