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How has a flesh-eating bacterium found in West Africa become endemic on the Bellarine and Mornington Peninsulas in Victoria?

That’s the question that’s puzzling a team of researchers and public healthcare workers led by University of Melbourne Professor Tim Stinear. Buruli ulcer (also known as Bairnsdale ulcer) is an infection of the skin and soft tissue caused by the bacterium, Mycobacterium ulcerans.

The toxin made by the bacteria attacks fat cells under the skin, which leads to localised redness and swelling or the formation of a nodule (lump) and then an ulcer.

Although Buruli ulcer is not fatal, the infection can often leave people with significant cosmetic, and sometimes functional, damage to limbs. In the last 10 years, annual cases in Victoria have increased by 1000 per cent.

“We’ve been studying the Buruli ulcer for more than 20 years now and we have strong evidence to suggest that mosquitos are vectors of the disease and possums are a wildlife reservoir,” explains Professor Stinear.

Professor Stinear is leading a world-first transmission intervention study to stop the spread of the bacteria. The project is funded by the National Health and Medical Research Council (NHMRC).

He is working in partnership with other investigators at the Doherty Institute, Barwon Health, Austin Health, CSIRO, Agribio, the University of Melbourne, Mornington Peninsula Shire, and Victoria’s Department of Health and Human Services.

Based on a series of epidemiological, field and laboratory-based studies, the Beating Buruli in Victoria project aims to actively disrupt disease transmission for the first time and to develop policies and guidelines based on evidence that can help stop the spread around Victoria and even globally.

“While we have made major advances in detecting and treating Buruli ulcer, there remain major questions to resolve around disease transmission.

“Our hypothesis is that targeted mosquito control in Buruli ulcer-infected areas will substantially reduce the incidence of disease in humans.”

Since the inception of the study in late 2018, Professor Stinear and his team have been systematically collecting possum faecal material from across the Mornington Peninsula.

They have collected possum ‘poo’ from over 2000 sites between Portsea and Rosebud and are testing these samples for Mycobacterium ulcerans.

“We are showing the clear, positive correlation between areas where possums are carrying the bacteria and humans are getting Buruli ulcer.”

In addition, the team are also continuing mosquito surveillance activities to test for the bacteria, while they plan for the mosquito control component of the study.

“When we have a disease outbreak, we have an obligation to the human population to control that disease. What we are trying to do is balance the need to control a devastating disease while minimising environmental impacts.”

This article was first published in the Celebrating Five Years of the Doherty Institute Impact Report.