Buruli ulcer in Australia (last update January 2013)
(Buruli ulcer, Bairnsdale ulcer, Daintree ulcer, Flesh Eating Bug, Mycobacterium ulcerans infection).
What is Mycobacterium ulcerans infection? Buruli ulcer, Bairnsdale ulcer and Daintree ulcer are all local names given to the same disease that is caused by Mycobacterium ulcerans, an environmental bacterium that produces a toxin that damages skin and underlying tissue. The infection occurs in humans in more than 32 countries. In the Australian state of Victoria, Buruli ulcer has also been found in possums, koalas, potoroos, dogs, cats and horses. In the popular press the infection is sometimes called the “the flesh-eating bug”. The toxin produced by Mycobacterium ulcerans (mycolactone) does kill tissue (flesh). However the disease progresses over days to weeks (not hours). Most severe cases of Buruli ulcer result from delayed diagnosis.
How do you get infected? Buruli ulcer is a geographically restricted infection (GRI). The means it is transmitted from the environment only in specific “endemic” areas. In Victoria (southeastern Australia) there is new evidence that mosquitoes transmit the infection but there may be more than one mode of transmission. Mycobacterium ulcerans does not appear to spread from person to person. Recent research in Victoria has shown that possums with chronic Buruli ulcer may be an important environmental reservoir of Mycobacterium ulcerans in Victoria. Whether an animal reservoir or mosquito transmission are involved in endemic areas outside Victoria is not known.
Which areas are endemic? In Australia cases occur most years in coastal Victoria, in far north Queensland from Mossman to just north of the Daintree river, the Capricorn Coast of southern Queensland and very occasionally elsewhere. So far no cases have been linked to Tasmania, South Australia, southern Western Australia or the ACT. Buruli ulcer does not occur in New Zealand.
How many cases? In 2011 there were 143 confirmed cases of Buruli ulcer in Australia reported to WHO; 78 were from Victoria, 65 from Queensland. Most of the cases in Queensland were linked to a small region of Far North Queensland between Mossman and just north of the Daintree river where there was an unprecedented outbreak which followed heavy summer rains. The disease is notifiable in Victoria and updated case numbers can be viewed on the Victorian Department of Health daily reports (see link to “Daily Reports” below). In 2012 there have been 75 new cases diagnosed in Victoria, most were from the Bellarine and Morningtion Peninsulas (see maps below). Overseas, Buruli ulcer is an emerging disease in rural West and central Africa where there have been thousands of cases in the last 25 years.
IMPOPTANT NOTE: There has been a marked increase in cases in both coastal Victoria and far north Queensland since 2011. For a sketch map of the endemic area in Far North Queensland, click here (click on “Box 1” in the opened document).
êGraph: Confirmed cases in Australia by year and state, 2004-2010.
êFigures: Google Earth image, confirmed cases Victoria, 2010.
êFigures: Google Earth image, confirmed cases on the Bellarine and Mornington Peninsulas, Victoria, 2010.
What are the symptoms and signs? The infection usually starts as a small spot (lesion) attached to the skin that enlarges over days to weeks. Some patients describe a dry scab that won't heal which then breaks down into an ulcer. Sometimes an insect bite is remembered but this is not universal. Lesions are usually (but not always) painless, and fever or other symptoms are usually absent. Eventually the spot breaks down at the centre and a slowly enlarging undermined ulcer appears but appearances can be variable and can be difficult to diagnsose. Lesions are typically solitary and mostly occur on the lower leg or arm. However, they can be anywhere. In Africa, a nodule (mobile lump) beneath the skin may be the first sign. Some patients present with plaques rather than ulcers or develop swelling of the whole limb or whole abdominal wall, without there initially being an identifiable nodule, plaque or ulcer.
IMPOPTANT NOTE: Some patients have said that the term “Buruli ulcer” is misleading, as an ulcer is not always present, leading to delayed diagnosis. Buruli (ulcer) is an important diagnosis to consider when people in endemic areas present with swelling of a whole limb even if no ulcer or necrotic area is initially apparent. Others have mentioned a scaly crusty lesion that doesn’t heal or ulcerate. “Buruli disease” may be a better descriptor than Buruli ulcer to remind clinicians of these variations in presentation.
How is Buruli ulcer treated? Buruli ulcer is slow moving and always curable although it can be quite destructive. A 2-month course of antibiotics appears able to kill the bacteria. Lesions may paradoxically worsen during antibiotic treatment. Surgery and antibiotics are often used in combination to achieve optimal outcomes.
Pictures (confirmed cases from Australia)
êEar: 2 year old child, coastal Victoria, Australia [Photo Clinical Photography, Royal Children’s Hospital, Melbourne]
êLeg, adult female, early diagnosis. [Photo: Dr. Paul Flood, Phillip Island].
êElbow ulcer, 9 year old girl, delayed diagnosis. [Photo: Clinical Photography, Royal Children’s Hospital, Melbourne]
êAnkle - 23 yo woman, plaque lesion (no ulcer apparent when diagnosed by biopsy)
[Photo: Dr. Paul Johnson, Austin Hospital, Melbourne]
êLower back ulcer - 12 yo boy. The markings show the area of palpable induration (swelling) that is more extensive than the ulcer itself.
[Photo: Mr. John Buntine, Melbourne]
Links to guidelines, articles and useful sites
Publications about Buruli ulcer on the Bellarine peninsula, Victoria, Australia
Buruli ulcer in Far North Queensland
World Health Organization
Emerging Infectious Diseases (Journal)
Public Library of Science (Journal)
Medical Journal of Australia
Proceedings of the National Academy of Science (Journal)
Stop Buruli (NGO)
Genome Research (Journal)
Department of Health (Victorian State Government)
Notes on diagnosis for clinicians
Rapid accurate diagnosis can be made by PCR directly from swab.
(Photo: Dr. Paul Johnson, Austin Hospital, Melbourne)
Specify “Mycobacterium ulcerans” or “Bairnsdale/Buruli ulcer” and “PCR” clearly in clinical notes on the request slip.
Details--DIAGNOSIS FROM A SWAB...PCR can be performed straight from the swab
1. If there is an ulcer, obtain a smear for acid fast bacilli (AFBs) using a swab that is run around the undermined edge (if present). Ensure there is some visible tissue material/fluid on the swab.
2. Request routine microscopy and culture and an AFB stain and PCR culture for M. ulcerans. VERY important: specify M. ulcerans PCR or write “Bairnsdale ulcer” in the clinical notes to ensure correct handling of the specimen.
3. If there is a suspicious necrotic skin lesion that has not ulcerated, or an acute oedematous presentation is being considered perform an incisional (punch), fine needle aspirate or excisional biopsy, and remember to ask for Mycobacterium ulcerans PCR (and histology, microscopy and culture).
Histological sections show extensive necrosis, and there are often large numbers of AFBs. PCR and culture of the biopsy specimens confirms the diagnosis. Granulomatous inflammation is sometimes seen in lesions that have been present for some time, and may herald the onset of healing. Culture takes 8-12 weeks, but you will need to treat the patient before culture results are available. PCR is more sensitive and much faster than culture.
NOTE: Negative swabs, and even negative incisional biopsies do not absolutely exclude the diagnosis because the organisms may not be spread evenly through the lesion. If in doubt, repeat biopsies.
êMicroscopy: Acid fast bacilli (M. ulcerans) in a smear taken directly from a swab of an ulcer. The bacteria can be clearly seen as red clumps on a blue background. This result can be available within 2 hours from a swab; if smear-positive the diagnosis is likely; a negative smear result does not rule it out. PCR is more sensitive than smear.
About this website
This is a privately funded website provided as a community service. The information is intended as a guide only and should not replace personalised medical advice from your doctor. Latest update January 2013
If you have questions/concerns about the contents or accuracy of this website please contact Dr. Paul Johnson by email: Paul.JohnsonATaustin.org.au (this email address is disguised to avoid automated SPAM; it can be recreated by replacing AT with the @ symbol)
Professor Paul Johnson (Austin Health Link)
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