
The Department of Health has issued a warning to people who have had diarrhoea not to enter any swimming pool, water spray park or other aquatic facility following a rise in Cryptosporidiosis cases in Western Australia.
In February 2025, there was an average of 70 cases a week of the diarrhoeal disease, well above the seasonal increase seen in summer in past years.
Cryptosporidiosis is caused by a microscopic parasite that causes an infection of the gastrointestinal tract.
It is easily spread from person-to-person in households, childcare facilities, and via swimming pools, waterparks, interactive fountains, and spas.
The most common symptoms include diarrhoea, stomach cramps and sometimes fever, nausea and vomiting.
Executive Director of Environmental Health Dr Michael Lindsay said that Cryptosporidium could easily spread to other people through water.
“An infected person can pass on cryptosporidiosis to other people if they don’t wash their hands properly after going to the toilet. Waterborne transmission can happen when people accidentally swallow contaminated water while swimming in pools or other aquatic facilities,” Dr Lindsay said.
“People may not realise they remain infectious for some time after diarrhoeal symptoms stop, so that’s why we’re asking people to avoid swimming for two weeks after their symptoms cease.”
The parasite can survive for long periods in water and the environment and is not destroyed by regular chlorination.
Aquatic facilities require proper water treatment procedures to maintain cleanliness, especially after any faecal incidents.
“The Department’s key priority is the prevention of further cases through alerting people about hygiene measures at pools and precautions to reduce the risk of spread in childcare facilities and household settings,” Dr Lindsay said.
It could take up to 12 days after exposure for symptoms to develop, and individuals may be infectious from the onset of symptoms until two weeks after symptoms resolve.
There is no specific treatment for the infection and symptoms may last a few weeks in some people.
Certain groups are more at risk of severe illness if infected, including younger children, pregnant women and people with weakened immune systems.