A surge in cryptosporidiosis cases has been reported in Victoria since the commencement of September 2023, with some instances linked to the use of public swimming pools.

Similar increases in cases have also been noted in several European countries and New Zealand.

Cryptosporidiosis, a form of gastroenteritis caused by the Cryptosporidium parasite, tends to escalate during warmer months when more individuals engage in swimming activities.

The resistance of Cryptosporidium parasites to standard chlorine levels in swimming pools contributes to outbreaks associated with pool usage.

In Melbourne, those exposed to swimming pools or in close contact with affected individuals face a higher risk.

While most cases result in mild and self-limiting illness, certain demographics, including young children, pregnant women, and immunocompromised individuals, are more susceptible to severe outcomes.

Symptoms of cryptosporidiosis typically include watery diarrhea and stomach cramps lasting several weeks, accompanied by fever, nausea, vomiting, bloating, and loss of appetite.

Some infected individuals may exhibit no symptoms.

Transmission occurs through the fecal-oral route, involving contaminated food and water, person-to-person or animal-to-person contact.

The incubation period ranges from 1 to 12 days, with an average of 7 days, and infected individuals remain contagious for up to two weeks after diarrhea cessation.

Preventive measures and recommendations for the public include refraining from swimming if experiencing diarrhea within the past 14 days, thorough showering before swimming, avoiding ingestion of pool water, practicing hand hygiene, especially after using the toilet or handling animals, and refraining from food preparation for others until at least 48 hours after diarrhea has ceased.

Additionally, changing diapers should occur in designated areas, and children should be kept home from childcare or school until symptom-free for 24 hours.

Individuals suspecting cryptosporidiosis are advised to consult a doctor who may request a stool sample for testing.

Positive results will prompt the doctor to offer guidance and notify the relevant health authorities.