Rare bacterial disease kills 20 with warnings issued to flood-stricken north Queensland

Scientists and health authorities have been left scrambling with ‘a lot of unanswered questions’ about why case numbers are spiking.

Muddy conditions in the aftermath of TC Alfred have heightened the dangers of soil borne disease present in the mud. Picture: NewsWire / Glenn Campbell

A rare bacterial disease which can cause brain damage has claimed over 20 lives this year, with fears that heavy rains in north Queensland could see cases skyrocket.

Infections of water and soil-borne disease melioidosis have been climbing since the start of the 2025, with Townsville recording its eighth death over the weekend.

Eleven people have died in Cairns and two deaths have been confirmed in Mackay.

Since January 1, a staggering 134 cases of the disease have been recorded across Queensland, roughly four times the average compared to the previous five years.

With 5 to 10 per cent of infections ending in death, authorities are gravely concerned about the spike in cases.

Melioidosis is primarily treated with intravenous antibiotics. (Supplied: Menzies School of Health Research)

Melioidosis is caused by bacteria that lives in soil and water, with infection occurring when the bacteria is inhaled through contaminated water droplets or makes contact with open wounds.

Townsville Health senior medical officer Mikaela Seymour said that the widespread flooding in February has contributed to the increase.

“There’s certainly an association with the amount of rainfall and the number of cases,” she said.

Heavy rainfalls can liberate the bacteria which would otherwise remain in soil below the surface, but this year’s heavy rain does not fully explain the rise in cases.

“We’ve had significant flooding in previous years, including the 2019 Townsville floods, but we certainly did not see this level of cases,” Dr Seymour said.

“So there’s a key factor this year that we don’t know about yet.”

Flash flooding in Townsville after heavy overnight rain. Picture: Evan Morgan

Dr Seymour urged residents to wear gumboots, gloves and a facemask around muddy water after flooding smashed north Queensland again this week.

“In the past we’ve seen melioidosis in areas where there has been significant road works or infrastructure changes,” she said.

“So we’re looking into that association between construction, soil movement and case numbers.

“But we have a lot of unanswered questions about where it’s located in the soil and why it’s in some places and not others.

“We’re asking everyone to take precautions.”

Flash flooding in Townsville after heavy overnight rain. Car park at Castletown. Picture: Evan Morgan

Whilst most people infected with melioidosis experience severe respiratory symptoms, a worrying number of cases have resulted in neurological impairment.

James Cook University associate professor of microbiology Jeffrey Warner said that in severe cases the disease can lead to memory loss, confusion and even long-term brain damage.

“Once the organism is in the bloodstream it can certainly cross the blood-brain barrier, causing an infection of the brain or encephalitis,” he said.

“Any brain infection will damage the tissue and the brain is not great at healing itself, so there can be ongoing neurological consequences.

Dr Warner is leading a James Cook University research program into the disease with hopes of answering key unknowns about the fatal bacteria.

“We will produce predictive models which will allow the development of tailored public health tools that will mitigate melioidosis risk in the changing Australian environment and climate,” he said.