​After a steep recent increase in cryptosporidiosis cases across the state, NSW Health is advising the community not to swim for at least two weeks after they've had diarrhoea.

Executive Director, Health Protection NSW, Dr Jeremy McAnulty said there had been 498 cases of cryptosporidiosis reported in NSW so far in 2024, compared to the 5-year average of 95 cases for the same time period.

Cryptosporidiosis is a diarrhoeal disease caused by the parasite, Cryptosporidium, which infects the intestine and is a common cause of acute diarrhoea in young children. Other symptoms can include nausea, vomiting, fever, headache, and loss of appetite.

Dr McAnulty said with almost half of the cases in children under ten years old, parents especially needed to be aware of the risks and precautions.

“Cryptosporidiosis is commonly acquired by swimming in and swallowing water contaminated with cryptosporidium parasites," Dr McAnulty said.

“The parasite survives for many days, even in chlorinated pools, and in the past very large outbreaks have been caused by people who had recently been infected going swimming.

“Almost half of the cases reported this year had been swimming during their exposure period, and with such a high proportion of young children affected and with many schools about to hold swimming carnivals, we're urging parents to stay alert for symptoms," he said.

People who have had diarrhoea should:

• avoid swimming for at least two weeks after your symptoms resolve
• avoid sharing towels for at least two weeks after your symptoms resolve
• avoid handling food for at least 48 hours after your symptoms resolve
• children who have diarrhoea should be kept home from preschool, childcare or playgroup until 24 hours after the diarrhoea has completely stopped.

To avoid catching cryptosporidiosis:

• avoid swimming in estuaries and inland waterways (e.g. rivers, creeks, dams) during and for at least three days after heavy rain
• avoid swimming at ocean beaches during and for at least one day after heavy rain
• avoid swallowing water when swimming
• wash your hands thoroughly with soap and water for 20 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.

​The increase in cases has also been experienced in Queensland, with further information available at Queensland Health. More information on cryptosporidiosis is available on the Cryptosporidiosis fact sheet.