Cryptosporidiosis: guidance, data and analysis

The characteristics, management and epidemiology of cryptosporidiosis.

Cryptosporidiosis is a disease usually caused by the parasites Cryptosporidium hominis and C. parvum. It is most commonly seen in children aged between 1 and 5 years. People with weak immune systems are likely to be more seriously affected. The most common symptom is mild to severe watery diarrhoea.

The parasites are resistant to chlorine. Outbreaks of cryptosporidiosis have been linked to drinking or swimming in contaminated water and contact with infected lambs and calves during visits to open farms.

The UK Health Security Agency (UKHSA) provides advice on controlling outbreaks of cryptosporidiosis and monitors any outbreak to find the source of the infection.


Managing outbreaks and cases of gastrointestinal infections.


Travel-associated infections

Updates to this page

Published 19 February 2013
Last updated 1 November 2023 + show all updates
  1. Added Cryptosporidium: public advice.

  2. Added new data to epidemiology section.

  3. Added Travel-associated Cryptosporidium 2014 report.

  4. First published.