Topic: Cryptosporidiosis
Description
Cryptosporidiosis is an intestinal infection caused by Cryptosporidium parvum, a microscopic parasite. Cryptosporidiosis occurs worldwide and appears to be a relatively common cause of acute diarrhoea in young children. As well as infecting humans, Cryptosporidium parvum occurs in a variety of animals including cattle, dogs and cats. In people with normal immune systems, the disease is generally not serious. However, people with weakened immune systems (eg. some people receiving cancer treatment, people on steroid therapy and people with HIV/AIDS) may develop severe and long lasting illness, which may contribute to death. The disease tends to be more common during the warmer months.
Symptoms
The most common symptom is diarrhoea, which is usually watery and may be profuse. Other symptoms that may occur are nausea, vomiting, fever, headache and loss of appetite. Some people infected with Cryptosporidium may not develop any symptoms.
In healthy young children, the illness is self-limiting and lasts only a few days. In people with normal immune systems, the symptoms often fluctuate but recovery is expected in less than 30 days. People with weakened immune systems may not be able to clear the parasite and the illness may persist.
Transmission
Cryptosporidium is shed in the faeces of infected humans and animals from the onset of symptoms and may continue to be excreted in the faeces for several weeks after symptoms have resolved. The infectious agent can survive in a moist environment for up to six months. It may then be transferred to humans in several ways:
- person to person contact (especially in households and child day care centres)
- handling of infected pets, farm animals, or their faeces
- food and water contaminated by the faeces of infected animals or persons, including swallowing contaminated recreational water
- exposure to faeces during sexual activities.
Cryptosporidium is resistant to the usual levels of chlorine in swimming pools and may survive for days. High doses of chlorine and cleaning of filters can remove cryptosporidium from a contaminated pool.
The time from contact with the parasite to development of illness is usually about seven days, but can be longer.
Treatment
There is no specific treatment for cryptosporidiosis. Replacement of fluid lost through diarrhoea may be needed. Persons with severe or long lasting diarrhoea should seek medical advice.
Prevention
There is no vaccination to prevent cryptosporidiosis and no way of preventing the illness in people who are known to have been exposed.
There are numerous precautions that can be taken to prevent exposure to cryptosporidiosis. These include:
- washing hands thoroughly after using the toilet, changing nappies and before handling food or eating
- washing the hands of toddlers and babies after a nappy change
- washing hands after contact with pets, and after cleaning up animal faeces
- washing hands after gardening or other direct contact with soil
- washing hands after contact with cattle and other farm animals
- washing fruit and vegetables before eating them
- not eating or drinking unpasteurised milk products
- not drinking untreated water and inadequately filtered water and boiling untreated water or water of unknown quality for at least one minute before drinking
- not swallowing water in swimming pools or other recreational water
- not sharing linen and towels during diarrhoea and for two weeks after diarrhoea has stopped.
People with weakened immune systems may need to take special precautions to reduce their risk.
Control
Children with diarrhoea should not return to child care or school until diarrhoea has ceased for 24 hours. Food handlers and health care workers should remain away from work until two days after diarrhoea has ceased.
As people with cryptosporidosis can remain infectious even after symptoms have settled, they should not go swimming while they have diarrhoea and for two weeks after diarrhoea has stopped.
Help and Assistance
For further information, please contact your local doctor, community health centre or nearest Population Health Branch.
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Footnotes
Heymann, D., ed. 2004. Control of Communicable Diseases Manual, 18th edition. Washington, DC: American Public Health Association.
Last Updated: 26th May, 2010
Date Valid to: 31st December, 2010
