Cryptosporidiosis fact sheet

What is cryptosporidiosis?

Cryptosporidiosis is an infection of the bowel caused by the Cryptosporidium parasite. It is one cause of gastroenteritis (‘gastro’).   

Cryptosporidiosis is spread by infected people or animals, or from contaminated food or water, including swimming pools. 

Cryptosporidiosis is a notifiable disease.

What are the symptoms?

Most common symptoms include: 

• watery diarrhoea 
• stomach cramps  

Less common symptoms include:

• fever
• vomiting 
• loss of appetite. 

Some people only have a mild illness or no symptoms at all.

Symptoms can develop from one to 12 days after becoming infected, usually within seven days.

In most people, symptoms usually last for several days but sometimes can come and go for up to four weeks.  People with weakened immune systems (e.g. people on steroid therapy, chemotherapy, and those living with HIV) may have severe and prolonged diarrhoea. 

Cryptosporidiosis is usually diagnosed by testing a faecal specimen sent to a laboratory. 

How is it treated?

Cryptosporidiosis usually resolves within a few days or weeks and without antibiotic treatment. However, symptoms may be more severe in people with a weakened immune system.

General advice for people with gastroenteritis includes: 

• Give plenty of fluids to avoid dehydration: fluids or oral rehydration solution (as per the instructions on the packaging) should be given regularly to replace lost fluids. Avoid drinks that are high in sugar, as these make diarrhoea worse. 
• Breastfed babies should continue to be breastfed throughout their illness.
• Resume bland, small portions of food, when hungry. 
• Medicine to prevent vomiting or diarrhoea should not be given, unless specifically advised by a doctor. 

Very young children (<6 months of age) or children with diarrhoea who refuse extra fluids should see a doctor. Anyone with prolonged or severe diarrhoea or with symptoms causing them concern should see a doctor.

How is it spread?

The Cryptosporidium parasite is excreted in the faeces of infected humans and animals.  Infection occurs when the parasite is swallowed. 

Infection is spread by:

• Drinking contaminated water or raw food.
• Swimming in contaminated water – in the ocean, rivers or swimming pools.
• Contact with someone who is infected, or touching objects that they have touched.
• Contact with infected animals or their faeces.
• Sexual contact with someone who is infected.
• Drinking unpasteurised milk or dairy products.

People with cryptosporidiosis can infect others while the parasite remains in their faeces, which may be for several weeks after symptoms have resolved.  The risk of infection decreases markedly after diarrhoea has stopped.

Very young children, the elderly, people with weakened immune systems and people who work or interact with farm animals are at greater risk of infection. 

The Cryptosporidium parasite is relatively resistant to chlorine and disinfection and therefore can be spread through contaminated swimming or wading pools.

How is it prevented?

How can I prevent getting cryptosporidiosis? 

• Wash your hands in warm soapy water for 20 seconds after going to the toilet, changing nappies, changing soiled linen, after gardening, after touching pets and other animals, and before you eat or prepare food.
• Change nappies on dedicated change tables, away from tables or counters where food is prepared or eaten.
• Regularly clean shared toys, books, equipment, furnishings, floors, nappy change areas and toilets (including toilet door handles).
• Don’t drink water from rivers, creeks, lakes and dams. If untreated water is the only available source, boil it for one minute before drinking or use in food preparation. 
• Try not to swallow water when you go swimming. Don’t swim in natural water sources if there has been heavy rain in recent days. 
• Never eat or drink unpasteurised dairy products.

How can I avoid infecting other people?

If you or your child has cryptosporidiosis: 

• Don’t prepare food that will be eaten by others until you have had no diarrhoea for at least 48 hours.
• If you are involved in food preparation or care for others in hospitals, aged care facilities or childcare, stay home from work while unwell and for 48 hours after your last loose bowel motion.  
• Keep children home from childcare or school while unwell and for at least 24 hours after their last loose bowel motion.
• Maintain good hygiene and handwashing practices, even after symptoms have ceased. 
• Do not swim, wade or paddle in public pools or other recreational water facilities for at least two weeks after symptoms have ceased.

Outbreak measures for cryptosporidiosis

• If there are two or more cases of cryptosporidiosis in a hospital, childcare centre, aged care facility or other institution call the Public Health Hotline on 1800 671 738 and ask to speak to a Clinical Nurse Consultant – Communicable Diseases. 
• Public Health Services can support the response to outbreaks of gastroenteritis.

For more information

If you have concerns about symptoms talk to your GP, or for after-hours care go to know your treatment options.

Visit the Healthdirect website at https://www.healthdirect.gov.au/cryptosporidiosis