WARNING - GRAPHIC IMAGES: A flesh-eating bug is on the rise in regional Victoria and researchers don't know how it is spreading.
Experts are calling for urgent government funding so they can figure out how to contain the bacteria, which causes an infectious disease called Buruli ulcer.
Most commonly found in west or central Africa and usually associated with stagnant water, it can have a devastating impact on sufferers, including long-term disability and deformity.
Victoria is facing a worsening epidemic, with 182 new cases in 2016 and 275 last year.
"We're in the midst of a serious epidemic. It's very difficult to prevent it and address it with effective public health interventions if we don't know that really basic scientific information,” Professor Daniel O'Brien wrote in the Medical Journal of Australia.
The cases are also becoming more severe and occurring in new areas, but efforts to control the outbreak have been thwarted, because it's not known how humans are infected, a study published in the The Medical Journal of Australia on Monday says.
"As a community, we are facing a rapidly worsening epidemic of a severe disease without knowing how to prevent it," researchers said.
"The time to act is now, and we advocate for local, regional and national governments to urgently commit to funding the research needed to stop Buruli ulcer."
Most cases in Victoria are occurring on the Mornington and Bellarine peninsulas.
Native and domestic animals, including dogs, cats, possums and koalas, have all developed the disease, but it's unknown whether they spread it.
The infection seems to happen more in warmer months and bites or trauma to the skin may play a role, the report says.
The ulcer can be treated with antibiotics, but patients end up paying about $14,000 each, because the drugs are not covered by the Pharmaceutical Benefits Scheme and many sufferers also require plastic surgery.
WHAT DOES IT LOOK LIKE?
The first sign of Buruli ulcer is usually a painless, non-tender blister-like nodule on the skin, often thought to be an insect bite.
A lesion may occur anywhere on the body but is most common on the limbs.
After one to two months, the nodule may begin to erode, forming a characteristic ulcer.
HOW IS IT TREATED?
In Australia and Japan, most lesions are detected early and diagnosed as a Category 1.
Treatment involves a combination of antibiotics, depending on the patient.
Many sufferers require plastic surgery.