Australia is hit by its largest parasitic outbreak in more than 20 years - and one group of people is getting sick at an alarming rate

Australia is fighting through its largest gastro outbreak in more than 20 years with an alarming number of toddlers falling ill.

Cases of cryptosporidiosis, a parasitical gastrointestinal disease, have soared with four times as many people falling ill than in all of 2023. 

Children under the age of four account for a quarter of the cases recorded.

The minuscule parasites are found in the faeces of pets, farm animals and humans.

The disease is spread in a variety of ways, including contact with someone who is infected and by drinking milk or dairy products that are unpasteurised. 

People can also contract the illness by swimming in contaminated water and need to be aware that chlorine does not kill the parasite's eggs. 

The illness can cause diarrhoea, fever, nausea and vomiting - with some people taking weeks to recover. 

Royal Australian College of General Practitioners Queensland deputy chair Dr Aileen Traves said doctors have noticed a spike in infection rates, particularly among kids.

Australia is fighting through its largest gastro outbreak in more than 20 years with an alarming number of toddlers falling ill

Australia is fighting through its largest gastro outbreak in more than 20 years with an alarming number of toddlers falling ill

'It’s difficult because there’s no treatment aside from resting and staying hydrated. The main thing we need people to do is to prevent spreading it,' she told the Sydney Morning Herald.

Some 11,747 cryptosporidiosis cases have been been recorded compared with 3,716 in 2023.

The cases are the highest recorded since the National Notifiable Disease Surveillance System began in 2001. 

Queensland is suffering the most from the outbreak with nearly half of all Australian cases recorded in the Sunshine State.

The higher rates have been credited to the fact more people are swimming in the state's warmer weather. 

Dr Traves said people who were vacationing were more likely to keep swimming on their holiday once the symptoms had stopped - but infected people need to wait 14 days to stop spreading infections.  

'It’s not isolated and as people travel, an outbreak somewhere can be spread really effectively,' she said.

The illness can cause diarrhoea, fever, nausea and vomiting - and people can take weeks to get better

The illness can cause diarrhoea, fever, nausea and vomiting - and people can take weeks to get better

Western Sydney University clinical academic gastroenterologist Vincent Ho said although outbreaks happened occasionally, winter will have less cases.

'We’d anticipate numbers to go down assuming there’s no vector for spread,' he said.

Mr Ho said weather events like big storms and floods spread the parasite, but droughts also can contribute to infection rates by increasing the concentration of the disease in rivers and dams.

Gastro cases, which is caused by bacteria such as salmonella, shigella and campylobacter, have also increased.

There were nearly 41,500 in the first six months of 2024 - a worrying figure as there were 61,320 in all of 2023.

To avoid gastro, residents have been advised to wash their hands properly, especially after touching animals, avoid consuming unfiltered water and to not swim following a heavy downpour.