Buruli Ulcer: How Possum Poo & Mozzies Are Spreading The Flesh-Eating Disease

April 11 2025, by Tatianna Gerard, 13 min reading time

You might think that possums rustling around your backyard or the odd mosquito bite is just part of Aussie suburban life—but what if they were part of something a bit more serious?

We’re talking about Buruli ulcer—a flesh-eating disease that’s been quietly spreading across parts of Australia. Caused by the bacteria Mycobacterium ulcerans, this infection starts off innocently enough: a painless lump or swelling, maybe a mozzie bite that doesn't quite heal. But if left untreated, it can lead to nasty ulcers, tissue damage, and a long road to recovery.

Although first identified in Victoria back in 1948, Buruli ulcer is making headlines again thanks to some eye-opening new research. A recent study led by the Barwon South West Public Health Unit and CSIRO found that the bacteria can be detected in possum faeces—often three years before human cases show up in nearby areas. In fact, in Victoria, Buruli ulcer is considered a zoonotic disease, meaning it can spread from animals to humans. Possums don’t just carry the bacteria—they can actually develop the disease and shed M. ulcerans into the environment through their droppings.

As of December 2024, Victoria has already recorded 344 cases of Buruli ulcer—and experts say the key to stopping it lies in better surveillance, mozzie control, and public awareness.

What is Buruli ulcer?

Buruli ulcer is a disease caused by a bacteria called Mycobacterium ulcerans, which produces a toxin that destroys skin and soft tissue. It usually starts out as a small, painless lump, bump, or swelling—often mistaken for an insect bite or minor irritation. But over time, that seemingly harmless spot can break down into an ulcer, sometimes eating through layers of skin and even muscle if left untreated.

It doesn’t hurt much in the early stages, which means many people delay seeing a doctor—until the ulcer is quite advanced. In more severe cases, people may need surgery or skin grafts to repair the damage. The good news is that if caught early, a course of specific antibiotics is usually effective in treating the infection and preventing long-term damage.

Buruli ulcer isn’t contagious between people. You can’t catch it from touching someone who has it. Instead, it’s thought to be picked up from the environment—likely through contaminated mosquito bites or cuts and scrapes exposed to the bacteria.

How possums and mosquitoes are involved in the spread of Buruli ulcer

Buruli ulcer isn’t spread from person to person. Instead, it’s considered an environmental disease, meaning people become infected through contact with bacteria present in the natural surroundings. Although the exact transmission pathway is still being studied, research suggests a complex cycle involving both wildlife and insects. Here’s how it likely works:

Here’s how the cycle likely works:

The bacteria (Mycobacterium ulcerans) exists in certain environments, particularly in coastal, wetland, or swampy areas where conditions are moist and sheltered.
Possums have been found to carry and develop the disease. These infected animals shed the bacteria through their droppings, which contaminates the surrounding environment—soil, water, plants, and even man-made surfaces.
Current research has shown that mosquitoes are believed to play a key role in transmitting the bacteria to humans. Mosquitoes may also bite infected possums, and then go on to bite humans, potentially carrying the bacteria directly from one host to another.
Humans are likely infected when a mosquito carrying M. ulcerans bites them, or when they have a scratch, cut, or abrasion that comes into contact with a contaminated area.

Where is Buruli ulcer being reported in Australia?

While Buruli ulcer was once considered a rare disease confined to isolated pockets, that’s no longer the case. In recent years, the number of cases has significantly increased—particularly in Victoria—and the disease is now appearing in more populated and urban areas.

Traditionally, most cases were concentrated along the Mornington Peninsula and Bellarine Peninsula, but recent data shows the infection is slowly moving into new regions, including parts of Melbourne and surrounding suburbs.

According to public health data, areas with notable increases in reported cases include:

Mornington Peninsula
Bellarine Peninsula
Surf Coast
Melbourne (selected areas)
Greater Geelong region, particularly:
- Belmont
- Highton
- Wandana Heights
- Newtown
- Grovedale
- Marshall

These locations have become areas of interest for health authorities due to the growing number of infections—and their proximity to possum populations known to be shedding Mycobacterium ulcerans in the environment.

What’s especially important to note is that Buruli ulcer is not limited to rural or bushland areas anymore. Cases are emerging in suburban communities, making it more important than ever for residents, holidaymakers, and outdoor enthusiasts to be aware of their surroundings and take precautions.

Even if you don’t live in these areas, it’s worth keeping an eye out if you’re visiting or spending time outdoors—especially during warmer months when mosquito activity increases.

How to protect yourself and your family

There are simple and practical steps you can take to reduce the risk of infection—especially if you live in or plan to visit a known hotspot area. Since the disease is believed to be spread through environmental exposure and mosquito bites, the best defence lies in protecting your skin and staying mosquito-smart.

1. Avoid mosquito bites

Since mosquitoes are believed to be one of the main carriers of Mycobacterium ulcerans, it’s important to make mozzie protection part of your daily routine.

Apply a reliable insect repellent when spending time outdoors—especially at dawn and dusk when mosquitoes are most active.Most effective repellents contain DEET or picaridin, both of which are proven to deter mosquitoes.

However, if you’re concerned about potential skin sensitivity, especially for children or those with sensitive skin, you can choose a natural alternative. Natural insect repellents typically use essential oils like citronella, lemon eucalyptus, lavender or tea tree, which have strong scents that mosquitoes dislike. While they may require more frequent application, they offer a gentler option for everyday use. One of the most reliable brands in Australia that offer natural insect repellents are Good Riddance. Check out the collection here at Aussie Pharma Direct.

2. Cover up when outdoors

Wear long sleeves, long pants, and enclosed shoes when you're gardening, hiking, or spending time in mosquito-prone areas. Light-coloured clothing is best, as it’s less attractive to mozzies than dark shades.

Check out our blog: Busting 11 Mosquito Myths: What’s True & What’s Not?

3. Eliminate breeding grounds

Mosquitoes love standing water. Tip out or remove anything in your yard that collects water—like buckets, saucers under plant pots, blocked gutters, birdbaths, or old tyres.You also need to clean pet bowls and outdoor containers regularly.

4. Keep possums at a distance

To help minimise the risk of environmental contamination, it’s best to avoid feeding possums or encouraging them to hang around your home. Make sure your bins are tightly sealed and free from food scraps that might attract wildlife. If you have sheds, roof cavities, or sheltered spots around your property, try to block off access where possible—possums love to nest in quiet, undisturbed areas.

5. Cover cuts and scratches

If you’re gardening or working outdoors, cover any open wounds or scratches with a waterproof dressing. Wash any skin breaks thoroughly with soap and water if they come into contact with soil or outdoor surfaces.

6. Be alert to early symptoms

One of the reasons Buruli ulcer can be tricky to catch early is that it often starts off quietly and painlessly—making it easy to overlook. If you notice a painless lump, swelling, or sore that doesn’t heal—especially after a mosquito bite—don’t ignore it.

Here are the symptoms of Buruli ulcer to look out for:

A painless lump, bump, or swelling: This is usually the first sign and may resemble an insect bite, pimple, or cyst. It often appears on the arms, legs, or other exposed areas of the body.
Redness or bruising around the area: The skin may begin to change colour, but it still might not feel sore or tender.
Progression to an open wound or ulcer: Over time—sometimes over days or weeks—the skin can break down, forming a deep ulcer with undermined edges. The sore may look alarming but still cause little or no pain, which makes it different from other infections.
Swelling of nearby limbs or joints: In some cases, especially if the infection spreads, people may experience swelling, reduced movement, or secondary infections in the affected area.
Delayed healing: Any wound or bite that doesn’t seem to be healing—especially if you’ve been in a known risk area—should be checked by a doctor.

See your GP promptly and mention any recent time spent in Buruli ulcer-affected areas. Early treatment with antibiotics can prevent serious complications.

Conclusion: Awareness is key when it comes to Buruli ulcer

Buruli ulcer is becoming increasingly relevant—especially in parts of Victoria where cases are on the rise and spreading into new areas. While researchers continue to investigate exactly how the disease is transmitted, current evidence suggests a strong environmental link involving possum droppings and mosquitoes, making prevention a community-wide effort.

When it comes to treatment, early medical intervention is essential. According to WHO, in Australia, Buruli ulcer is typically managed with a combination of antibiotics and supportive therapies. A commonly used regimen includes rifampicin and moxifloxacin, which have shown positive results in routine practice—though its effectiveness hasn’t yet been validated through a randomised trial. However, a more recent study suggests that rifampicincombined with clarithromycin is now the recommended treatment, offering another effective option for managing the disease.

At this stage, there are no established primary preventive measures for Buruli ulcer. Prevention focuses on reducing exposure—especially avoiding mosquito bites and minimising contact with contaminated environments. The BCG (Bacillus Calmette–Guérin) vaccine, often associated with tuberculosis, appears to provide only limited protection and is not currently relied upon as a preventive strategy for Buruli ulcer.

Until more definitive answers are available, the best thing you can do is stay informed. Take precautions when spending time outdoors, especially in high-risk areas, protect yourself from mosquito bites, and keep an eye out for any unusual skin lumps or sores. Spreading awareness can help protect your family, your neighbourhood, and your wider community.