With Victoria on track to see a record number of cases of the Buruli ulcer this year, researchers are investigating whether a new culprit could be behind the persistent spread of the flesh-eating disease into parts of Melbourne.
Scientists have already shown a link between possums, mosquitoes and the transmission of Mycobacterium ulcerans, the bacteria that cause the ulcer, to humans.
However, with possums being largely territorial animals, the key question of why the epidemic has been moving geographically remains a mystery.
The Buruli ulcer has plagued residents on the Mornington Peninsula for the past decade or so and it still remains most prevalent there.
But, over the past six years, increasing numbers of cases have cropped up in different parts of Geelong, west of Melbourne.
The disease has also spread across Moonee Valley, with a recent spike of cases in Essendon, Moonee Ponds and Strathmore.
The Merri-bek suburbs of Coburg, Brunswick West and Pascoe Vale South have also seen a rash of infections, prompting the Western Health Public Health Unit (WPHU) to issue a Buruli ulcer warning last month.
The first locally acquired case of the ulcer in New South Wales was also reported last month in Batemans Bay.
Leading Buruli ulcer expert Daniel O'Brien, who is the director of infectious diseases at Barwon Health, believes one possible answer to the spread of the disease could lie with another animal – foxes.
A potential connection between foxes and the Buruli ulcer was first flagged in a study published last September and carried out by researchers at Barwon Health, Deakin University and Australia's national science agency, the CSIRO.
O'Brien, who was a co-author of the study, said the research threw up an interesting curveball when it showed 30 per cent of fox faeces tested were positive for Mycobacterium ulcerans.
In one of the 20 fox faeces samples tested, the bacteria was alive, suggesting transmission was possible.
"We might have found another vector, because what's never been explained very well is why is this disease moving into all these new areas," O'Brien said.
"Possums are very territorial, they actually don't move very much.
"It might be that there's something else moving – a fox roams far and wide, and therefore, it's possible they're involved in the transmission."
The same research team is now investigating the hypothesis further by testing foxes and their faeces from a broad geographical area on the Bellarine Peninsula.
Meanwhile, another study also co-authored by O'Brien, published last month, has helped shed light on which people are most at risk of developing the Buruli ulcer.
People with diabetes are two times more likely to be diagnosed with the flesh-eating ulcer, while tradies working outdoors, especially in contact with soil, were also more likely to contract the disease, the study found.
The insights are important because the number of cases of the Buruli ulcer are at a record high, with 377 cases detected in Victoria over the past 12 months.
So far this year, there have been 259 cases recorded in the state, compared with 220 over the same period last year.
"Last year we saw the highest number of cases we've ever had in Victoria, and this year, we're already 15 – 20 percent up on last year's," O'Brien said.
"The problem is still here, if anything it's getting worse."
'I wouldn't wish it on anybody'
Glenn Diamond, who lives on the Mornington Peninsula, said he suddenly developed his ulcer after doing a bit of gardening in the backyard.
"I had been transferring soil into some wine barrels to grow stuff in," he said.
A week later, Diamond noticed a small, red rash about the size of a thumbnail on his right elbow.
"The next day I saw that it had gotten bigger and it was starting to look like it was getting infected," Diamond said.
Diamond went straight to see his GP, who immediately suspected it was a Buruli ulcer, despite never having seen one in real life.
A swab test confirmed the diagnosis.
For Diamond, the ulcer proved to be excruciatingly painful and long-lasting.
"It's a terrible thing. I wouldn't wish it on anybody," he said.
"On a scale of one to 10, I think the pain was probably about a 10. When it was at its peak, it was awful."
Diamond's treatment included a two-hour surgery to debride the infected tissue.
The ulcer took one year to heal completely and Diamond was left with a 12.5-centimetre scar.
Diamond said he was thankful to the doctors and nurses who managed to save his arm.
"It was touch and go for a while," he said.
"They did tell me later on that there was a possibility I'd lose my arm."
Diamond said his saving grace had been in catching the ulcer early.
"I've known people who were misdiagnosed," he said.
"One lady told me her doctor was treating her for a spider bite. She is two years down the track and she's still having trouble."
Diamond said he hoped sharing his story would encourage people to get medical advice as soon as possible if they suspected they might have a Buruli ulcer.
"The key to it is, if you're in any doubt at all, get to your doctor and demand a swab," he said.
"Don't mess around thinking it might be a spider bite."
What you can do to avoid a Buruli ulcer
- Wear long pants and long-sleeved clothing when you're outdoors, especially if you're working in the garden in the soil.
- Apply mosquito repellent to areas of skin that are exposed.
- Cover up any wounds before coming in contact with soil.
- If you injure yourself, immediately wash the wound in soapy water and put some antiseptic on it.
Contact reporter Emily McPherson at em********@******om.au
