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

Last updated: 23 March 2018

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, Cryptosporidium hominis causes the most infections in humans in Australia.

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 (usually 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 often occurs through:  

  • person-to-person contact, particularly in families and among small children (for example, in child care centres)
  • swimming in contaminated pools, spas and recreational water parks 
  • handling infected animals or their manure
  • sexual contact with the risk of faecal exposure
  • drinking contaminated water, such as from untreated bores and wells
  • drinking untreated milk
  • food such as raw fruit, vegetables and salads (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 recreational swimming water
  • people who drink untreated water (for example, from rivers or lakes)
  • travellers to developing countries ravellers 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 by bringing to a rolling boil is sufficient to kill Cryptosporidium
  • Do not eat or drink unpasteurised milk or dairy products
  • Avoid swallowing water when swimming
  • Avoid swimming in natural waters (e.g.​ rivers, creeks, dams, surf) within a week after heavy rain
  • If you are immunocompromised, take further steps to avoid contact with animals and environments that could be contaminated by faecal matter, for example, by asking someone else to clean up after pets.  If you must clean up after a pet, use disposable gloves.

People travelling to developing countries should:

  • wash hands thoroughly with soap and water after going to the toilet and before eating
  • avoid uncooked foods, including fruit and vegetables unless you are able to peel them yourself
  • not drink untreated water, including ice and drinks mixed with water.  Instead, drink bottled or boiled water
  • avoid eating from street stalls

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 preschool, childcare or playgroup until 24 hours after the diarrhoea has completely stopped.

How is it diagnosed?

To diagnose cryptosporidiosis your doctor will order a stool test. 

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.

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