An intestinal infection caused by a protozoal parasite, often leading to watery diarrhoea and fever

  • More common in children
  • Poor personal hygiene is a risk factor
  • Gender and genetics are not significant factors

Cryptosporidiosis is caused by a protozoal parasite known as Cryptosporidium parvum. It is an intestinal infection that is spread through contact with infected people or animals or by intake of contaminated food or water. The disease occurs worldwide, but is more common in developing countries because of poor hygiene. In developed countries, outbreaks may be due to contamination of reservoirs. Cryptosporidiosis is often severe in people with reduced immunity, such as those with AIDS (see HIV infection and AIDS).

In some cases, there are no symptoms. In others, watery diarrhoea, abdominal pain, fever, nausea, and vomiting may develop a week after infection. The symptoms usually last 14–28 days, and most otherwise healthy people make a full recovery. However, people with reduced immunity may have persistent symptoms and develop severe malnutrition and dehydration, which can be fatal.

What might be done?

Cryptosporidiosis is usually diagnosed by examining a sample of faeces under a microscope for the parasite. There is no effective treatment to cure this infection, but, if your symptoms are severe, you may need hospital treatment with intravenous fluids and antidiarrhoeal drugs. If a local outbreak of the disease occurs, you should boil all your drinking water to kill the parasite.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

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