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Rise of flesh-eating ulcers in Australia’s Victoria state leaves scientists searching for answers

South China Morning Post logo South China Morning Post 11/4/2021
a group of people on a beach with a city in the background: People are seen on a beach near Melbourne, in Australia’s Victoria state. Buruli ulcer cases have been found in parts of the inner city, but are more common along the coast. Photo: EPA People are seen on a beach near Melbourne, in Australia’s Victoria state. Buruli ulcer cases have been found in parts of the inner city, but are more common along the coast. Photo: EPA

Australian property stylist Ali Waight thought she had a mosquito bite when a red welt appeared on her left leg in early 2018. But within days, the mark had "developed into a massive hole".

What followed was almost a year of fatigue and misery for the 45-year-old, who lives in the coastal town of Point Lonsdale, an hour's drive south from Melbourne.

"I wasn't allowed to play with my three kids, I wasn't allowed to go swimming, go to work, ride my bike, walk the dogs, I couldn't even walk. It just went on and on and on. It was just debilitating," she said.

Waight was diagnosed with Buruli ulcer, a disease caused by flesh-eating bacteria that can lead to large open wounds, and if untreated, permanent disfigurement and disability.

The disease first emerged in the Australian state of Victoria in the early 1900s, but cases have skyrocketed in recent years, with the state recording 277 in 2017, 340 in 2018, 299 in 2019 and 218 last year. This year, 38 cases have appeared so far - an increase compared to the same period in 2020.

Waight thinks she was infected with the flesh-eating bacteria after being bitten by a horsefly. She had two surgeries - one in July 2018 and another in January 2019 - and was treated with antibiotics that she said affected her mental health.

"I was just so extremely tired and felt depressed - I know of others who have had to stop taking them after 48 hours because of the impact on their mental health," she said. "It's the same medication used to suppress leprosy so it's super strong stuff."

Some people who get an ulcer recover quickly if they are able to get it cut out, so Waight said the length of time she took to return to normal left her feeling that others thought she was just overreacting.

"It wasn't until I came across a Facebook group for people who have dealt with similar circumstances that I realised I wasn't alone," she said.

The reality is it's actually not that uncommon to have multiple people in the family get it now
Tanya Webster, whose sons had Buruli ulcer

In the group, she found hundreds of other sufferers who had shared their stories. Some had lost limbs, while others said they had been misdiagnosed by as many as six different doctors. All appeared equally mystified as to how they caught the disease.

In Australia, the average age of Buruli ulcer patients is around 60, according to the World Health Organization, but children are not immune. Tanya Webster's 16-year-old son caught the disease in 2016 and was still left with a significant dent in his hand after 18 months of recovery - then last year, the nurse's two-year-old was confirmed with it on his arm as well.

"I just thought, 'how unlucky am I' but the reality is it's actually not that uncommon to have multiple people in the family get it now," she said.

CREEPING PROBLEM

Outside Victoria state, Buruli ulcer is mostly found in impoverished parts of central and western Africa where the chances of patients going untreated remain high. A handful of cases have also been reported in Japan, Papua New Guinea and South America.

Scientists believe the ulcer - as with up to 75 per cent of emerging diseases, including Covid-19 - is zoonotic, meaning it made the jump from animals to humans. The bacteria that causes it, Mycobacterium ulcerans, is related to that which causes leprosy but it is not thought to spread through human-to-human transmission, meaning there is little risk of it spreading across the globe.

Yet even after decades of research, the disease is still poorly understood. Victoria state seems an unlikely destination for it to thrive, given how much more common it is in tropical areas, and there has been a worrying increase in infections outside of the seaside areas where it has more traditionally been found in Australia.

The best guess at the moment is it goes from marsupials to humans through mosquitoes
Ary Hoffman, infectious-disease specialist

The state's health department warned last month that several Buruli ulcer cases had been found in parts of inner Melbourne, making it "the first non-coastal area in Victoria to be recognised as a potential area of risk" - though active transmission is still more likely along the coast.

"There's a lot we still don't know," said Ary Hoffman, a University of Melbourne professor specialising in infectious diseases. "There's plenty of data indicating that it does depend on possums and mosquitoes, so the best guess at the moment is it goes from marsupials to humans through mosquitoes."

It was also not known why infections seemed to be spreading more rapidly and becoming more severe, he said.

"There's multiple factors that could be contributing (to this). Is it that there's more interaction between humans and marsupials? Are mosquitoes more abundant? We just don't know," he said.

a koala hanging on a tree branch: Marsupials, such as koalas, could be a disease vector for Buruli ulcer. Photo: Kyodo © Provided by South China Morning Post Marsupials, such as koalas, could be a disease vector for Buruli ulcer. Photo: Kyodo

Hoffman said that while some progress has been made in understanding the disease, "we're definitely not over the trickiest hurdle yet".

"People know what to look for when you have a Buruli problem, but on the transmission side, we still somehow need to break the connection between marsupials, mosquitoes and humans," he said.

Speaking to Australian broadcaster ABC in 2018, Daniel O'Brien, an associate professor at Barwon Health, Victoria's largest health care provider, said the Buruli ulcer cases he was seeing were getting more severe.

"The ulcers are more aggressive, they're bigger, it causes more tissue destruction, but it also means treatment is much more difficult and leaves longer-term consequences," he said.

A LARGER INTERVENTION

Meanwhile, Australian federal and state authorities, along with the National Health and Medical Research Council, a government body overseeing the country's health and medical research, have devoted AU$3 million (US$2.28 million) to a research programme that is searching for answers.

For now, scientists say a more immediate way to tackle infections is to reduce the mosquito population. "At the moment, we're in the pilot stage, using a combination of source reduction of mosquitoes and by using sticky traps to remove mosquitoes from properties," Hoffman said.

"Once we have the data on that and see if you can non-chemically reduce the mosquito population, we'll move onto plans for a larger intervention which will tackle the whole mosquito-possum interface."

The disease specialist said residents could help by cleaning out gutters regularly and keeping household waste to a minimum, so as to reduce the number of potential breeding sites for mosquitoes.

Webster, whose sons had Buruli ulcer, said there needed to be more public awareness of the disease, especially among visitors to Victoria state, where popular tourist destinations such as Mornington Peninsula, the Great Ocean Road and Philip Island are located.

"I always go up and talk to random people on the beach - I will tell them about the risks, just to be proactive, wear mosquito repellent, don't leave stagnant water lying around. It's not to scare people but just to make sure people are aware," she said.

Webster also urged those who thought they might have caught the disease to get tested - pointing to how her second son had to be tested twice before the infection was confirmed. "It would have been so much worse had I just left it," she said.

For Waight, the property stylist, there needs to be greater awareness of the disease. She said communities with a high risk of infections could put up signs reminding visitors to monitor themselves for symptoms, while doctors should also be made aware of the trend of rising infections.

"One thing that seems to be coming up often, especially in areas that haven't dealt with it for as long, is people going to a doctor and being turned away because the doctor doesn't know what it is. There's just such a lack of knowledge," Waight said.

Hoffman, meanwhile, said he felt positive that research on the ulcer was ramping up, with scientists now testing hypotheses "that have been around for a while".

"We're now trying to get to the stage where we can implement some randomised trials," he said. "So, for the next few years, what this means is instead of relying simply on what we think is going on, we'll be relying on some hard data."

This article originally appeared on the South China Morning Post (www.scmp.com), the leading news media reporting on China and Asia.

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