Cryptosporidiosis is a disease caused by swallowing the Cryptosporidium parasite. It mainly causes diarrhoea and stomach cramps.

Last updated: 01 July 2012

What is cryptosporidiosis?

  • Cryptosporidiosis is a diarrhoeal disease caused by the parasite, Cryptosporidium, which infects the intestine.
  • Cryptosporidium infections have been reported in humans and in a variety of farm, pet and native animals.
  • Although there are several species of Cryptosporidium, only Cryptosporidium parvum and Cryptosporidium hominis are thought to cause infection in humans.

What are the symptoms?

  • The most common symptom of cryptosporidiosis are watery diarrhoea and stomach cramps. Other symptoms may include fever, nausea, vomiting and loss of appetite. Some people with the infection have no symptoms at all.
  • The first signs of illness appear between 1-12 days (average 7 days) after a person becomes infected.
  • Symptoms may come and go and may last days to weeks. People with a weak immune system may have more severe symptoms that can last for months.

How is it spread?

Cryptosporidium is present in the faeces matter of infected humans and animals. Infection occurs when the parasite is ingested. Transmission most often occurs through:  

  • Person-to-person contact, particularly in families and among small children (for example, in child care centres)
  • Drinking contaminated water
  • Swimming in contaminated pools
  • Handling infected animals or their manure
  • Food (in rare cases).

A person is most infectious when they have diarrhoea, but the parasite may be excreted for several days after symptoms disappear.

Who is at risk?

People who are most likely to become infected with Cryptosporidium include: 

  • People in close contact with others who have cryptosporidiosis
  • Children who attend day care, including children in nappies
  • Parents of infected children
  • Child care workers
  • Swimmers who swallow even small amounts of swimming pool water
  • People who drink untreated water (for example, from rivers or lakes).
  • Travellers to developing countries
  • People who work with animals
  • Men who have sex with men

People with weakened immune systems are at risk for more serious disease and should see their doctor if symptoms develop.

How is it prevented?

To avoid catching cryptosporidiosis: 

  • Wash your hands thoroughly with soap and water for 10 seconds after using the toilet, handling animals or their manure, changing nappies, working in the garden and before preparing food or drinks
  • Do not drink untreated water (for example, from lakes or streams). Boiling water will kill Cryptosporidium
  • Avoid swallowing water when swimming
  • Avoid swimming in natural waters (e.g.​ rivers, creeks, dams, surf) within a week after heavy rain

When travelling in developing countries, avoid food or drinks that may be contaminated (for example, raw vegetables, tap water or ice made from tap water).

To avoid spreading cryptosporidiosis, people with cryptosporidiosis should:  

  • Not swim for at least two weeks after the diarrhoea has stopped
  • Not share towels or linen for at least two weeks after the diarrhoea has stopped
  • Not handle food for at least 48 hours after the diarrhoea has stopped.

Children who have diarrhoea should be kept home from school, preschool, childcare or playgroup until 24 hours after the diarrhoea has completely stopped.

How is it diagnosed?

Cyptosporidiosis is confirmed by going to a doctor and having a stool specimen tested.

How is it treated?

There is no specific treatment for cryptosporidiosis. Drink plenty of fluids to avoid dehydration.

What is the public health response?

Laboratories are required to notify cases of cryptosporidiosis to the local Public Health Unit under the Public Health Act, 2010. Public Health Units investigate cases, and review possible sources of infection to prevent further spread.

Por further information please call your local Public Health Unit on 1300 066 055