Midway through 2011, far north Queensland doctors began seeing people presenting with nasty ulcers that were turning surrounding tissue into sludge. It was an outbreak of what’s known locally as Daintree ulcers – a condition that’s been known for many years now, but no-one’s really sure how humans acquire it, and thus how it can be prevented.
By the end of that year, GPs & surgeons had treated many cases – with strong antibiotics and surgical procedures. It can be cured, but it can take a long time and sometimes there’s lasting damage. In FNQ, Daintree ulcers occur only in a very contained and specific area of the Daintree region – no-one yet knows why. It’s a more common problem in parts of west Africa – so the common theme is tropical climates. But the mystery deepens – these ulcers also occur in the very un-tropical East Gippsland district of Victoria, where they’re called Bairnsdale ulcers. The World Health Organisation now calls them Buluri ulcers, in acknowledgement of their incidence in west Africa.
We know what causes them – a bacteria called mycobacterium ulcerans. It’s a bacteria commonly found in the lush tropical world, but for reasons no-one can yet explain, they cause flesh-eating ulcers in just a few relatively small, quite specific but widely separated areas, one of them not at all tropical. We don’t know how the bacteria gets into humans. Mosquitos, march flies, possums and other critters have all been suspects – there’s no definitive answer and some believe the rainforest itself could be the vector. And we don’t know why some people who’ve been exposed don’t get sick, while others develop serious ulcers.
A team of researchers is in FNQ at the moment trying to answer those questions. They hope to develop a blood test to detect exposure and help us prevent future outbreaks. Professor Paul Johnson, from Melbourne University & Austin Health is one of the researchers.