A flesh-eating ulcer has taken root in a NSW holiday hotspot and poses a significant risk of spreading to Sydney.
Batemans Bay on the state’s south coast has become an endemic centre for Buruli ulcer, infectious disease experts have warned, after two confirmed cases were genetically linked to an earlier infection in another NSW town.
Buruli ulcer is the same flesh-eating infection responsible for outbreaks in Melbourne after it spread from coastal getaway hotspots in 2021. Victoria has confirmed 347 cases of Buruli ulcer so far this year.
Researchers suspect mosquitos have carried the flesh-eating bacteria from possums to humans, as occurred in Victoria.
The ulcers develop when Mycobacterium ulcerans bacterium releases a toxin that eats away at the skin and subcutaneous soft tissue.
A median incubation period of five months means it can take months before patients see a doctor. Weeks after a non-healing sore appears, the wound collapses, leaving a gaping ulcer.
The Batemans Bay cases were a 94-year-old man with an ulcer on his left ring finger in 2020 and a 71-year-old man whose ulcer developed from a mosquito bite on his right arm in 2023.
In PLOS Neglected Tropical Diseases on Tuesday, Victorian and NSW researchers proposed Batemans Bay was “a new endemic focus of human Buruli ulcer transmission”.
“This risk for further spread along coastal NSW is significant,” they warned.
Co-author Professor Paul Johnson, a Buruli ulcer expert at Austin Health and Melbourne University, said there was a significant risk of spread to Sydney.
“If you look at what’s happened in Victoria, it has taken years, but ... there are increasingly large amounts of cases,” Johnson said.
“It’s now in Melbourne, Geelong, all along the Mornington and the Bellarine Peninsulas, so quite major population centres.”
There have been no confirmed locally acquired NSW cases since 2023.
Genomic testing showed bacterium samples from the Batemans Bay cases were identical and genetically related to an earlier case in Eden, 150 kilometres south of Batemans Bay.
“It looks like the bacteria got into NSW and adapted locally [in possums and mosquitos],” Johnson said.
NSW residents should think about preventing mosquito bites wherever they live, even though the risk is very low, Johnson said.
The ulcer “used to be a much more terrifying disease” but is now easier to diagnose, provided patients and doctors have awareness, he added. Treatment is antibiotics and dressing.
Dr Anton Forsyth, a senior medical advisor at Murrumbidgee Local Health District, which includes Batemans Bay, said not enough was known about the disease and how it came to the coastal town to stop transmission.
“We have moved to a hope that we can control and track the disease,” Forsyth said.
The local public health unit raised awareness about the potential transmission risk from mosquitos and symptoms, particularly among GPs.
“We don’t know if Buruli is going to spread in NSW, but it certainly is a possibility we need to be prepared for,” Forsyth said.
How to minimise your risk:
- Avoid mosquito bites: wear shoes, long sleeves and trousers and apply repellent.
- Wash and cover wounds sustained outside while working, playing or gardening.
- See your doctor if you are concerned.
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