Buruli ulcer in Australia
(September 17th 2016) Short URL: goo.gl/h3a0b4
What is Buruli ulcer? Buruli ulcer, Bairnsdale ulcer, Mossman ulcer and Daintree ulcer are all local names given to the same disease that is caused by Mycobacterium ulcerans--a mycobacterium related to those that cause TB and leprosy. “Buruli ulcer” or just “Buruli” is the official name preferred by WHO. Mycobacterium ulcerans produces a toxin that damages skin and subcutaneous fat tissue. The infection occurs in humans in more than 32 countries.
Which areas in Australia and New Zealand are endemic? Buruli is a geographically restricted infection so only occurs following contact with specific “endemic” areas. In Australia these include coastal Victoria, north Queensland near Mossman, the Capricorn Coast of Queensland near Yeppoon and the tropical north coast near Darwin (see map). So far no cases have been linked to Tasmania, South Australia, southern Western Australia or the ACT. There have been a handful of cases in Southern New South Wales near the border with Victoria. Buruli does not occur in New Zealand.
How do you get infected? Travel to an endemic area even for just a few hours is enough to pick up the infection. The median incubation period is 4.5 months with a range of 3 weeks to almost a year. In Victoria (southeastern Australia) there is evidence that mosquitoes transmit the infection, but other biting arthropods may be involved, or there may be more than one mode of transmission. Mycobacterium ulcerans does not appear to spread from person to person.
How common? In 2013-14 there were 163 confirmed cases of Buruli ulcer in Australia, giving an annual national incidence of < 1 per 100,000. However in endemic regions this can be up to 100 times higher. Overseas there have been thousands of cases of Buruli, predominantly in rural areas in west and central Africa.
Map: Confirmed cases Australia since 1939 (Courtesy A/Prof John Hayman: circle size indicative only).
Map: Confirmed cases Australia, 2013-14 (WHO Meeting on Buruli ulcer, March 2015, Geneva). Circle sizes are to scale in this map
Graph: Confirmed cases in Victoria by year. [Acknowledgement: A/Prof John Hayman, cases prior to 1993].
Figure: Overlaid Google Earth image, likely place of infection, confirmed cases Victoria, 2013-14 (WHO Meeting on Buruli ulcer, March 2015, Geneva).
Circle sizes are to scale in this map.
When to suspect Buruli ulcer? “Buruli” may be a better term than Buruli ulcer, as not all lesions are ulcers and this can confuse patients and doctors.
Buruli usually starts as a small spot (lesion) on or under the skin that enlarges over days to weeks. Lesions are typically solitary and typically occur around the ankles, backs of calves or elbows. However, they can be anywhere. Sometimes an insect bite or episode of trauma is recalled. Lesions are usually painless, and fever or other symptoms are usually absent. Eventually the spot breaks down and a slowly enlarging undermined ulcer appears but appearances can be variable and Buruli ulcer is difficult to diagnose if your doctor is not familiar with the condition.
Some patients present with a raised reddish plaque rather than an ulcer or develop swelling of the whole limb or whole abdominal wall without an identifiable nodule, plaque or ulcer. Buruli progresses over days to weeks (not hours). Most severe cases of Buruli ulcer result from delayed diagnosis.
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. Recently updated treatment guidelines for Australian clinicians are available here.
Pictures (confirmed cases from Australia)
Ear: 2 year-old, coastal Victoria, Australia [Photo Clinical Photography, Royal Children’s Hospital, Melbourne]
Leg, adult female, early diagnosis. [Photo: Dr. Paul Flood, Phillip Island].
Elbow ulcer, 9 year-old girl, delayed diagnosis. [Photo: Clinical Photography, Royal Children’s Hospital, Melbourne]
Lower back ulcer - 12 year-old boy. The markings show the area of palpable induration (swelling) that is more extensive than the ulcer itself.
[Photo: Mr. John Buntine, Melbourne]
Notes on diagnosis for clinicians
IF THERE IS AN ULCER OR DISCHARGING LESION:
Rapid accurate diagnosis can be made by PCR directly from swab of an ulcer. Make sure you get some biological material on the send of the swab by running it around the undermined edge of the ulcer.
If there is a plug of necrotic tissue, moisten this with saline. If there is biological material on the swab, the PCR is almost always positive.
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; make sure you get biological material on the swab (see picture). Moisten and rub with saline if necessary.
IF THERE IS PLAQUE, SWELLING or CELLULITIS BUT NO ULCER, fresh tissue from an incisional biopsy, punch biopsy, fine needle aspirate or excisional biopsy will be needed. Remember to ask for Mycobacterium ulcerans PCR microscopy and culture. Histology is also very helpful.
Ankle - 23 year-old woman, plaque lesion (no ulcer apparent; diagnosed by histology and PCR on a incisional biopsy)
Microscopy: Acid-fast bacilli (Mycobacterium 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. PCR confirmed this is M. ulcerans
Links to guidelines, articles and useful sites
Department of Health (Victorian State Government)
Publications about Buruli ulcer in Victoria, Australia
Buruli ulcer in Far North Queensland
Buruli ulcer in central Queensland
World Health Organization
Public Library of Science (Journal)
Medical Journal of Australia
Proceedings of the National Academy of Science (Journal)
Genome Research (Journal)
About this website
short URL: http://goo.gl/h3a0b4
This is a privately funded website provided as a community service. The information is intended as a guide only and should not replace medical advice from your doctor. Latest update August 2016. If you have questions/concerns about the contents or accuracy of this website please contact me by email: Paul.JohnsonATaustin.org.au Professor Paul Johnson (Austin Health Link)
Professor Paul Johnson
Austin Health & University of Melbourne
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