Health alert:
Date Issued:
07 Mar 2013
Issued by:
Dr Rosemary Lester, Chief Health Officer, Victoria
Issued to:
Health professionals in all regions of Melbourne

Key messages

  • The Department is investigating a four-fold increase in Cryptosporidium notifications since January 2013.
  • Many cases are reporting exposure to swimming pools in their incubation periods, and other settings representing a risk for onwards transmission are households and childcare facilities.
  • Whilst all people are susceptible to becoming infected, certain groups are more likely to become seriously ill including younger children, pregnant women and individuals with weakened immune systems.
  • Health professionals are requested to maintain a high index of suspicion for Cryptosporidiosis in individuals presenting with gastroenteritis.
  • If you suspect Cryptosporidium infection, ask about likely exposures such as household contact with infected individuals, recent visits to swimming pools, close contact with farm animals (refer to the Blue Book for additional information), send a stool sample requesting Cryptosporidium testing and provide infection control and exclusion advice.
  • Cryptosporidiosis is a Group B notifiable disease and requires notification by fax, online or in writing within five days.

What is the issue

Cryptosporidiosis is a parasitic disease that most commonly causes gastroenteritis. Since January 2013, there has been a substantial increase in Cryptosporidium notifications, While initially focussed on southern and eastern metropolitan Melbourne, an increase in notifications is now affecting Melbourne’s northern and western region. The organism lasts for long periods in water and the environment and is not destroyed by regular chlorination. In this outbreak there appears to be a role for transmission related to swimming pools and the key priority is the identification and prevention of further cases through hygiene measures at pools, childcare facilities and in household settings where there are cases. The Department is working with pool managers to ensure effective measures are in place to address the issue.

Who is at risk

All people can become infected and the risk appears to be greatest for those exposed to swimming pools or for those who are household contacts of cases.

Although most illness is mild and self-limiting, certain groups are more at risk of severe illness if infected, and these are younger children, pregnant women and individuals with weakened immune systems, especially HIV/AIDS – these individuals are at serious risk of prolonged and life-threatening illness.

Symptoms and transmission

The most common presentation is gastroenteritis, with symptoms including watery diarrhoea, cramping abdominal pain, bloating, vomiting and fever. Less commonly, Cryptosporidium infection can present as pneumonia, cholecystitis or pancreatitis.

After exposure it can take up to 12 days to develop symptoms, which then last between 4 to 21 days. Individuals are potentially infectious from the onset of symptoms until two weeks after becoming asymptomatic.

Transmission occurs by the faecal-oral route (person to person and animal to person), and via ingestion of contaminated water or foods.

Prevention and treatment

Clinicians are requested to maintain a heightened awareness of the possibility of Cryptosporidium infection and when considered, to take the following actions in addition to standard treatment advice focused on hydration:

  • Enquire about potential exposures including swimming pools in the two weeks prior to onset;
  • Send a stool sample requesting testing for Cryptosporidium;
  • Advise the patient or their parent (if relevant) about the importance of hand hygiene measures and if relevant advise exclusion from childcare settings until 24 hours free of symptoms;
  • Advise exclusion from swimming pools until 14 days free of symptoms; simple steps on preventive measures to reduce the risk of cryptosporidium contamination are available at


Cryptosporidiosis is a Group B notifiable disease and requires notification by fax, online or in writing within five days.

Written notifications can be made: