Melioidosis, a rare antibiotic-resistant disease caused by bacteria found in soil or mud, often surfaces in tropical areas after heavy rain or flooding.

While cases have occurred in Queensland in previous years, the state’s tropical public health services director Jacqueline Murdoch said 2025 “absolutely is a record-breaking year”.

“Certainly we haven’t seen anything like this,” she told national broadcaster ABC this week.

There have been 94 total infections in the state since the start of the year, Queensland Health data shows.

Infection only occurs if the disease is inhaled or enters a person’s bloodstream, and most of the patients contracted the disease by breathing it in, Murdoch said.

As her team investigates the spike in cases, she noted that “the climate has something to do with it”.

Queensland, in northeastern Australia, experienced heavy flooding after storms dumped more than 1.5m of rain in parts of the state this month, engulfing homes, businesses and roads.

Melioidosis has a fatality rate of up to 50% because the “organism is very aggressive and resistant to antibiotics”, University of Tasmania food microbiologist John Bowman said.

People with weaker immune systems were most at risk of contracting the disease, he added.

Symptoms include fever, difficulty breathing, coughing and headaches.