A parasite found in water and which is resistant to chlorine has been linked to a surge in gastroenteritis cases in South Australia.
SA Health has reported 164 cryptosporidiosis cases in 2024, compared with 33 cases at the same time last year and 196 total cases in 2023.
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Cryptosporidiosis or cryptosporidium is transmitted by drinking or swimming in contaminated water or consuming infected foods.
It can also be spread through touching surfaces contaminated with infected people or animals faeces.
The parasite causes a bowel infection that leads to gastro.
Symptoms include watery diarrhoea with stomach cramps, fever, and sometimes vomiting and loss of appetite.
Symptoms can last for up to two weeks for people with normal immune systems, or longer for people who are immunocompromised.
The Australian Medical Association South Australian president Dr John Williams said young children are at greater risk of infection.
“It’s common in children because of their poor hand hygiene and proximity to each other, so they pass it onto others quite quickly,” he said.
SA Health said very high levels of chlorine are needed to kill cryptosporidium otherwise it can survive in the water for several days.
“If people do have gastro symptoms, it’s best of course to stay away from public places and swimming pools,” Williams said.
“If you are tested positive for cryptosporidium you need to stay out of the water for 14 days.”
The parasite also led to health departments in Queensland and NSW earlier this year warning people to stay away from swimming pools if they had diarrhoea.
In Queensland, more than 700 cases were reported in January 2024 — 13 times more the number of cases in January 2023.