More than 820 cases have been reported so far this year, which is more than 13 times higher than the same period last year.
The most common places of infection are public pools and water parks, where the cryptosporidium parasite that causes gastro thrives.
“Probably one of the worst things I’ve ever had in my life, I could probably compare it to childbirth, pretty terrible,” mother Kate Perman said after catching it.
The majority of Queensland cases have been recorded in West Moreton, Darling Downs, Central Queensland, Townsville, and Mackay Hospital and Health Service regions.
NSW and Victoria are also reporting similar increases.
Children under nine are the most at risk, accounting for about 40 per cent of all cases.
Chief Health Officer Dr John Gerrard said cryptosporidium was usually acquired through the ingestion of contaminated water or food, or through contact with infected individuals or animals.
“This can occur in various settings including swimming pools, water parks, and other recreational water facilities where water may be contaminated with faecal matter,” Gerrard said.
“The most common symptom of cryptosporidiosis is diarrhoea, especially in young children.
“Other symptoms include nausea, vomiting, fever, headache, and loss of appetite.
“People with cryptosporidiosis can remain infectious for a short time after symptoms have ended.”
He said people with symptoms should avoid swimming in public places for at least 14 days after infection.