Quick reference for doctors, vets and concerned citizens provided by Paul Johnson, Infectious Diseases Physician and Buruli researcher.
Advice provided is of a general nature, see your doctor if you are concerned!
(Latest update January 2024)
Confirmed Buruli ulcer – Victoria Australia
What is Buruli ulcer caused by?
Buruli ulcer (Buruli) is an infection of skin and underling soft tissue caused by Mycobacterium ulcerans (MU). Infection is from the environment to you, not from person to person. You only get infected in very specific places (“endemic areas”), as MU is not everywhere. In the world there are at least 33 countries with endemic areas. In Australia active endemic areas include coastal towns in Victoria and now inner suburbs of Melbourne and Geelong, far North Queensland between Mossman and the Daintree River and most recently Bateman’s Bay in New South Wales. Most Australian Buruli is acquired in Victoria.
What does a Buruli ulcer look like?
Typically, Buruli lesions are single, slowly progressive and occur on exposed parts of the body where mosquitoes bite you. An ulcer may not be there initially. A hallmark of Buruli is it just keeps progressing and does not respond to standard antibiotics. People usually seek medical help after a few weeks because of persistence and increase in size, and sometimes older people think they may have a skin cancer. There are other presentations too – more rapid swelling and redness of a whole limb or part of a limb (cellulitis) or a raised red lesion without an ulcer (plaque). Anyone can get Buruli ulcer including children.
How do you get infected with Mycobacterium ulcerans?
In Victoria Buruli is transmitted by mosquitoes, although we are not sure this is the same all over the world. A major breakthrough in understanding Buruli in Victoria came when we discovered that possums, particularly ringtail possums, also suffer from Buruli ulcer. Wherever there are human cases we find possums with Buruli living in the trees above, and possum excreta on the ground below that tests positive for Mycobacterium ulcerans by PCR. Mosquitoes pick up Mycobacterium ulcerans from possums by direct contact (eg. by biting possums with Buruli lesions) or indirect contact (eg. from contaminated possum excreta in house gutters and street drains). Transmission in Victoria occurs in the mosquito season (summer and autumn) but people with confirmed Buruli are most often diagnosed in winter and spring. This paradox is explained by the long incubation period, typically around 5 months.
How do you prevent Buruli ulcer?
Buruli is transmitted by mosquitoes in endemic areas. If you live in or visit a Buruli endemic area, protect yourself against bites and reduce mosquito breeding sites on your property.
How do you diagnose Buruli ulcer?
Diagnosis is straightforward once you or your doctor think of Buruli. If there is an ulcer, a doctor can obtain a swab. Make sure that biological material is visible on the swab before sending. You may need to rub the central plug of dead tissue with the swab or soak it in saline and go back to the plug to loosen it up, to ensure a good sample. It is essential to write “Buruli ulcer PCR and culture” clearly on the pathology request form. The PCR test is very accurate if the swab is collected correctly.
How do you diagnose Buruli if there is no ulcer yet?
If there is a suspicious progressive cellulitis or plaque, then a punch biopsy is needed. Do not swab in tact skin, the infection is below the skin and the test will be falsely negative. Once again it is important that the biopsy specimen is sent for “Buruli ulcer PCR and culture”
Buruli plaque lesion – progressive increase in size over 4 weeks:
What is the best treatment for Buruli ulcer?
Standard treatment is 8 weeks of two special oral antibiotics given together – rifampicin and clarithromycin. This will reliably kill Mycobacterium ulcerans but it takes much longer to fully heal. People typically need regular dressings for many weeks after completing their curative antibiotics.
Can Buruli ulcer heal by itself?
Occasional patients may be able to spontaneously heal their own ulcers without surgery or antibiotics. At present though we recommend antibiotics for everyone.
Does Buruli get worse before it gets better?
YES, sometimes anyway. Buruli “Paradoxical reactions” or “IRIS” (immune reconstitution inflammatory syndrome) is most likely in those with large ulcers or plaques. This happens because active antibiotics stop the production of toxin allowing your own immune system to get to work. You may notice increased swelling, redness, pain, a larger ulcer or even new ulcers. There may also be profuse drainage of liquefied fat which will be full of dead bacteria. This is part of the natural healing process and is not usually a sign of a new or out of control infection. You may need specialist advice to guide your through this phase of your recovery.
Buruli ulcer in animals for vets
Victoria is almost unique in the world for naturally occurring cases of Buruli ulcer in a range of species other than humans. It is not clear whether M. ulcerans has a very special ecology here or this anomaly is just due to heightened awareness because of the ongoing human epidemic. For unknown reasons the two most susceptible vertebrates appear to be ringtail possums and humans! Clinically significant Buruli ulcer has also been identified in cats, dogs, horses, alpacas and possums (so far). Sick possums or occasionally other species are often brought to vets in Buruli endemic areas. Currently these include the whole of the Mornington and Bellarine Peninsulas, the inner northern suburbs of Melbourne and some suburbs in Geelong. A confirmed case in a possum in a non-endemic area is an important indicator and should be reported to your local public health unit.
Pictures: Ringtail possum nose and tail lesions (see full articles below from 2010 and 2014).
Attributions for photos: O’Brien CR et al 2014 https://doi.org/10.1371/journal.pntd.0002666; Fyfe JA et al.2010 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2919402/
Links to published articles on Buruli ulcer in Animals:
Buruli ulcer and Australian wildlife (Wildlife health Australia)
Mycobacterium ulcerans in two horses in south-eastern Australia (2010)
A Major Role for Mammals in the Ecology of Mycobacterium ulcerans (2010)
Localised Mycobacterium ulcerans infection in four dogs (2011)
Mycobacterium ulcerans infection in two alpacas (2013)
Buruli ulcer in humans and animals (2013)
Clinical, Microbiological and Pathological Findings of Mycobacterium ulcerans Infection in three Australian Possum species (2014)
Links to public information on human Buruli ulcer
South East Public Health Unit (SEPHU) – information on Buruli ulcer
Barwon Southwest Public Health Unit – Buruli in Geelong
Victorian Department of Health – Buruli alert (October 2023)
Links to selected new publications
e-life Journal: Possums and Buruli ulcer in Victoria, Australia (2023)
Skin swab study of healthy volunteers in endemic regions of Victoria (2023)
Season of transmission in Victoria (2023)
Transmission of Buruli ulcer and the Philosophy of Science (Nature Research Communities Blog)
Links to key past Scientific Papers – pathogenesis, epidemiology, reservoir and transmission
Development of the Mycobacterium ulcerans diagnostic PCR (1997)
First detection of Mycobacterium ulcerans in the environment (1997)
Insects in the transmission of Mycobacterium ulcerans (1999)
Mycolactone – the toxin produced by Mycobacterium ulcerans (1999)
A plasmid encodes production of mycolactone by Mycobacterium ulcerans (2004)
Incubation period of Buruli ulcer in Victoria – 1 (2013)
Location of 649 Buruli lesions on the human body, Victoria, Australia (2017)
Incubation period of Buruli ulcer in Victoria -2 (2018)
Skin temperature variation does not explain Buruli lesion distribution (2020)
Podcasts on Buruli ulcer in Australia:
Breaking Buruli Part 1 – ABC Science Friction (Paul Johnson and Tim Stinear)
Breaking Buruli Part 2- ABC Science Friction
Spot Diagnosis – Skin Institute
Buruli in Victoria -(graph) confirmed cases by year.
Buruli became notifiable in Victoria in 2004. Prior data courtesy of Professor John Hayman.
Editorials in The Lancet
Buruli ulcer: Here today but where tomorrow?
Buruli ulcer: Cured by 8 weeks of antibiotics?
Surgery for Buruli ulcer in the antibiotic era
Buruli ulcer in the News (Australia)
Early Europeans commenting on the mosquitoes in and around Melbourne (from “The Birth of Melbourne” edited by Tim Flannery)
Richard Howitt, Melbourne 1840:
“The mosquitoes are, confound them, keen as death”
J.B. Were, Melbourne, 1859:
“I suffered much annoyance from the mosquitoes. They attack new comers for the first 2-3 months very fiercely…”
Charles Kean, Melbourne 1864:
“The mosquitoes are counted in myriads”
About this website
Professor Paul Johnson is an Infectious Diseases Physician who for 30 years has led and co-led Buruli research teams in Victoria. Early breakthrough funding was provided by the Royal Children’s Hospital Research Foundation and then the Victorian Department of Health (previously DHHS). We particularly thank Dr. Rosemary Lester, former Chief Health Officer, for her vision and support when Buruli was rare. Few others could see the risks that lay ahead for expansion of endemic areas and the increase in incidence we are now experiencing in Victoria. Together we developed the Buruli diagnostic PCR now used worldwide, were the first to identify Mycobacterium ulcerans in the environment anywhere, identified possums as the local environmental reservoir and mosquitoes as the mode of transmission in Victoria. Paul also has extensive clinical experience with Buruli ulcer and developed the first Australian Buruli Consensus treatment guidelines in 2007 which have since been updated with my colleague A/Prof Dan O’Brien in 2014. Paul has been a member of the WHO Technical Advisory Group on Buruli ulcer since 1998.
Link to University of Melbourne
Comments welcome, please contact me ([email protected])
This website is provided as a public service. It replaces a long standing predecessor hosted by ozemail (which no longer exists!)
(http://members.ozemail.com.au/~groverjohnson/Mulcerans.htm)