Australia is in the grips of a cryptosporidiosis outbreak


Data from the National Notifiable Diseases Surveillance System reveals cases of cryptosporidiosis have skyrocketed in 2024.

During the fortnight from 5–18 February, there were 1,333 cases reported nationally, compared to 93 during the same period in 2023.

Caitlin Davies MPSThe Health Departments from three states – Queensland, New South Wales and Victoria – have issued alerts for both health professionals and patients after a significant rise in cases over the summer months.

Queensland-based pharmacist Caitlin Davies MPS said she has ‘definitely seen an increase in “gastro”’ cases locally.

‘I spoke to some of the GPs, who said there is a lot of gastro around but no one really wants to get stool samples done to diagnose,’ she said.

Key practice points

  • refer patients with gastro symptoms to a GP for a stool sample test for Cryptosporidium
  • advise patients with Cryptosporidium infection not to swim for 2 weeks after symptoms have resolved.
  • inform parents to keep children home from childcare centres or school until 24 hours after symptoms have resolved.

Brisbane-based pharmacist Michael Nance has also noticed a ‘big increase’ in cases compared to previous years.

‘In the past week I have seen four cases of this presentation for azithromycin suspension for children and at least two adults [who] were not related to the children,’ he said. ‘The children all had scripts from Queensland Children’s Hospital, and the adults had GP [issued] scripts.’

Here’s what pharmacists need to know about the fast-spreading parasite.

What is cryptosporidiosis and how does it spread?

Cryptosporidiosis, a form of gastroenteritis, is caused by the Cryptosporidium parasite. The condition can occur when a small amount of oocysts are orally ingested. While human-to-human and animal-to-human (faecal to oral) are the most common modes of transmission, the parasitic infection can be transmitted through contaminated food and water.

The incubation period for symptoms to manifest can take anywhere between 1–12 days after infection with the parasite.

Most cases of cryptosporidiosis occur in children under the age of 10, with the parasite commonly transmitted in daycare centres.  When a significant amount of adults are infected, waterborne transmission is likely – either from inadequately treated drinking water, or swimming pools and dams. 

The surge in cryptosporidiosis cases this year is largely due to an increase in recreational water activities, said Dr Vincent Ho, clinical academic gastroenterologist to the School of Medicine at the University of Western Sydney.

‘In general, cases of cryptosporidiosis increase during the warm spring and summer months when people are out and about in the water,’ he said. ‘Many of the cryptosporidiosis cases reported likely acquired their infection through the use of public swimming waterholes and pools.’

To that end, public swimming pools across the affected states have recently closed for periods of time in order to curb the rising spread of cryptosporidiosis.

‘Drinking or accidentally swallowing water contaminated with Cryptosporidium parasites is a common mode of transmission,’ said Queensland Chief Health Officer Dr John Gerrard. ‘This can occur in various settings including swimming pools, water parks, and other recreational water facilities where water may be contaminated with faecal matter.’

What’s the difference between gastro and cryptosporidiosis?

Symptoms of cryptosporidiosis include:

  • watery diarrhoea 
  • abdominal pain or cramping
  • nausea
  • vomiting
  • loss of appetite
  • low fever.

Dr Ho told Australian Pharmacist that the symptoms of gastroenteritis and cryptosporidiosis are identical. 

‘Gastroenteritis is a more general term referring to inflammation of the stomach and intestines typically caused by bacterial or viral infection,’ he said. ‘Cryptosporidiosis, given that it principally involves the gastrointestinal tract, can therefore lead to gastroenteritis in affected individuals.’

What are the treatment options?

Most people will not require specific treatment for cryptosporidiosis as the condition is self-limiting, said Dr Ho. ‘Typically, symptoms resolve within 2 weeks,’ he added. 

However in some patients, such as young children, cryptosporidiosis can lead to dehydration.

‘It’s recommended that oral rehydration solutions purchased from the pharmacy be used to help in rehydration,’ said Dr Ho.

If there is concern a patient is suffering from significant dehydration, they are having difficulty maintaining an appropriate fluid intake, or if symptoms are severe or persist well beyond the 2-week mark, they should be referred for medical evaluation, said Dr Ho.

‘Pharmacists should also be aware that certain individuals, such as those with significant immunocompromise, may be at greater risk from cryptosporidiosis and therefore there would be a low threshold for referring such individuals for medical evaluation if troubling symptoms persist,’ he said.

This includes patients who:

  • live with HIV or AIDS
  • have cancer
  • recently had a stem cell transplant
  • are on immunosuppressive medicines.

In some cases, azithromycin can be used in Australia for cryptosporidiosis treatment, said Dr Ho.

‘Strictly, its use is best reserved for the aforementioned cases where symptoms are severe, prolonged or in specific cases such as those that have a compromised immune system,’ he said. 

‘Some clinicians may elect to use it on younger children affected with cryptosporidiosis on a case-by-case basis.’

How can pharmacists help to minimise the spread?

Due to the rise in recent cases, cryptosporidiosis should be considered in people presenting with gastroenteritis, particularly if they have gone swimming in a public pool in the last 2 weeks, said Victorian Chief Health OfficerDr Clare Looker.

Pharmacists should refer with view to pathology for a stool sample test for Cryptosporidium, and any other relevant investigations for gastroenteritis.

Pharmacists should advise patients with Cryptosporidium infection not to swim for 2 weeks after symptoms have resolved. Children should also not attend childcare centres or school until 24 hours free of symptoms.

It’s important to wash hands thoroughly after going to the toilet, changing nappies, and after cleaning up animal faeces to minimise transmission of disease. You should also wash the hands of toddlers and babies after a nappy change,’ added Dr Gerrard.

Other precautions include:

  • washing hands after contact with pets, and after cleaning up animal faeces
  • washing hands after gardening or contact with soil
  • washing hands after contact with farm animals
  • washing fruit and vegetables before consumption
  • avoiding unpasteurized milk products
  • avoid drinking untreated or inadequately filtered water, and boiling water of unknown quality for at least 1 minute before drinking
  • showering before and after swimming in recreational pools and splash parks
  • don’t swim in rivers, creeks, dams, or beaches within a week after heavy rain
  • avoid sharing linen and towels during bouts of diarrhoea and for 2 weeks after diarrhoea has stopped.