Deadly diseases after flood events

As communities get back to some normality after ex-Tropical Cyclone Alfred swept through northern regions of East Australia, Townsville, Brisbane and the Gold Coast, a silent but deadly danger is lurking in the mud. Burkholderia pseudomallei, the bacteria that causes melioidosis, lives in soil and becomes a serious health risk after heavy rain or flooding. Already in 2025, this rare bacterial infection has claimed at least 16 lives in Queensland, with authorities warning that it is moving farther south than ever before.

What is melioidosis?

Melioidosis is not a household name, but in regions north of Rockhampton, particularly during the wet season, it’s a known threat. The bacteria responsible for it lives between 10 and 90 centimetres below ground, usually harmless until extreme weather events cause it to rise to the surface where it can contaminate floodwaters, drinking water supplies, and even become airborne.

Humans can become infected through open wounds, drinking contaminated water, or simply breathing in dust or droplets from affected soil. While animals can also contract melioidosis, the risk of human infection from animals is considered low. Still, there have been occasional reports of domestic pets testing positive in Queensland’s southern areas.

Why this year is different

The recent surge in cases is deeply concerning. While most infected people experience only mild symptoms like a fever or skin lesion, the disease can turn deadly — particularly for people with compromised immune systems, diabetes or kidney disease.

This year’s outbreaks have followed in the footsteps of Cyclone Alfred, which left behind floodwaters and saturated soils perfect for the bacteria to spread. The death rate for melioidosis is 10% to 20% in Australia, even with our high-quality healthcare. Compare that to Southeast Asia, where the rate can soar to 40% due to limited access to treatment. Even in Australia, these numbers show how dangerous melioidosis can be, especially when left undiagnosed or untreated.

Climate change and the southern spread

What makes this year’s situation even more alarming is where new cases are being found. Traditionally limited to tropical regions above the Tropic of Capricorn, melioidosis is now showing up in places like Brisbane and the surrounding areas — well below the historical range.

This shift is likely tied to climate change. Warmer temperatures and increased rainfall are expanding the environments where the bacteria can survive. Flooding in recent years has confirmed locally acquired cases in the Brisbane flood plains, and scientists are now watching the Gold Coast and northern New South Wales with growing concern.

The trend is clear: as southern regions become wetter and warmer, the bacteria finds new places to call home. And for communities unfamiliar with melioidosis, the risks may go unnoticed until it’s too late.

It’s important to understand that the risk doesn’t disappear when the rain stops. The bacteria can remain active in the soil for weeks, even months, after a weather event. Until the mud dries up and the ground stabilises, the threat of infection remains.

Why this poses a risk for reinstatement and claims management

Following a catastrophic (CAT) event, multiple stakeholders respond quickly to assess damage, manage risk and begin property reinstatement. These professionals are often exposed to more than just the physical destruction and compromised infrastructure. A less visible but significant threat emerges ― health risks that are not immediately apparent or controllable.

In a recent case, whilst investigating a major claim, I became unwell on the third day of the project. Initially assumed to be a short-term stomach bug, the condition worsened over the next two days, leading to severe pain and discomfort. After seeking medical assistance and undergoing various treatments, I was diagnosed with COVID-19 on day seven. This incident underscores that COVID-19 remains a relevant concern — even on remote, post-disaster sites.

This situation highlights the possible health risks that can impact claims and reinstatement operations, especially after natural disasters like the recent Queensland floods. These include:

• Skin infections from contact with contaminated floodwaters and mud
• Intestinal diseases due to consumption of or contact with unclean water
• Respiratory infections, particularly from mould and airborne pathogens
• Mosquito-borne diseases, as standing water can become a breeding ground
• Leptospirosis, contracted through contact with water or soil contaminated by animal urine
• Melioidosis, a rare but serious infection caused by bacteria found in soil and water in northern Australia

Such illnesses can delay recovery efforts, pose risks to on-site teams and complicate the broader claims management process. Awareness, health precautions and timely medical intervention are essential components of an effective post-disaster response.

Protecting yourself during clean-up

The clean-up after a storm is always urgent, but it’s during this time that people are at the highest risk of exposure. For those stepping into mud and floodwater, especially individuals who are older or living with chronic illnesses, the stakes are particularly high.

Here’s how you can stay safe:

• Avoid contact with floodwater and mud wherever possible, especially if you have open cuts or wounds. 
• Wear protective gear like gloves, waterproof boots and long sleeves when cleaning up debris or walking through affected areas.
• Use masks if you’re working in areas with dust or dried mud that might be disturbed and go into the air.
• Practice good hand hygiene — wash your hands thoroughly after any clean-up work, especially before eating or drinking.
• Boil your water before use if there’s any risk it’s been contaminated by floodwaters.
• Watch for symptoms like unexplained fever, skin sores, chest pain or fatigue — and seek medical advice early if they appear, especially if you’ve recently been exposed to environments affected by flooding.

Supporting recovery efforts safely 

Melioidosis may be rare, but it is deadly — and its reach is expanding. As climate conditions change, what was once a problem confined to northern Queensland is now becoming a broader concern for communities farther south. With the flood clean-up continuing and impacted areas slowly returning to normal, awareness is the first step toward protection. Don’t underestimate the mud beneath your feet. Take every precaution, especially if you or your loved ones are in vulnerable health groups. If you’re helping out after a flood or storm, suit up and be mindful of the invisible risks that come with the recovery.