Buruli ulcer / Bairnsdale ulcer

see also:

• mycobacteria

• a chronic ulcer caused by Mycobacterium ulcerans, which, in southern Victoria, is thought to be spread by the common backyard Australian mosquito, Aedes notoscriptus with the possum being the reservoir in endemic areas which are mainly those that are or were swamp lands
• new tech allows identification of local endemicity even before human cases¹⁾
• see also Better Health Victoria - Buruli ulcer

• Future Microbiol. 2011 Oct; 6(10): 1185–1198. Treating Mycobacterium ulcerans disease (Buruli ulcer): from surgery to antibiotics, is the pill mightier than the knife?

• in 1948, in Melbourne, Australia, this organism was found to be the cause of chronic skin ulcers in Bairnsdale, Victoria and endemic in Buruli, Uganda.
• the skin ulcers have been called Bairnsdale ulcers, Daintree ulcers in Qld, ulcerans, Buruli ulcers, Kumusi ulcer, ‘sik bilong Sepik’ in Papua New Guinea, the ‘Tora ulcer’, in the Congo and also known as the ‘Mexican ulcer’ in Latin America.
• whilst primarily occurring in Bairnsdale region in Victoria, it has migrated westwards, appearing in Philip Island and Mornington Peninsula in the 1990s, then in early 2000's, cases have been found in Victoria's Bellarine Peninsula region and as far north as Sandringham by 2019
• reported severe cases in Port Philip region (particularly in Rye and surrounding townships of Sorrento, Blairgowrie and Tootgarook) have been doubled in the 5 years from 2012-2017
• diagnoses in Victoria have increased from 89 in 2014 to 336 in 2018 ²⁾
• in 2019, cases were also being reported in Belmont and in Airey's Inlet
• in 2021, cases were reported in the Essendon, Moonee Ponds and Brunswick West areas from an apparently common source
• in 2024, it became endemic in Batesmans Bay. NSW coast after 1st cases noted in 2023. Genome sequencing of cases in this area and in Eden has revealed a distinct M. ulcerans genotype, suggesting the pathogen is extant in NSW similar to the situation in Victoria.
• in 2024, there were 347 reported cases in Victoria

May 2022 endemic regions in Victoria

• chronic, usually painless, slowly growing skin ulcer without systemic symptoms
• incubation period 4wks-9 months (median 4-5 months)
• appears to have a higher risk in those aged > 60yrs or those under 15 years
• diagnoses in Victoria peak June-Nov but occur all year
• not transmissible from person to person unless ulcers with large numbers of organisms contact broken skin

• swabs or biopsy taken from the ulcer
  • If an ulcer is present or if a scabbed lesion can be deroofed, two dry swabs (or pre-moistened with sterile saline) from beneath the undermined edges of the lesion should be sent for staining for acid-fast bacilli (AFB), M. ulcerans PCR and culture.
  • It is essential that there is visible clinical material on the swab.
  • The key to accurate diagnosis is that M. ulcerans is found in the subcutaneous fat layer. This can only be accessed with a swab if an ulcer has already formed.
  • If an eschar cannot be deroofed or in the event of atypical presentation with plaque, oedema and/or cellulitis, a superficial swab will likely return a false negative and will not be useful.
    • In these cases, a fine needle aspirate (FNA), punch biopsy, or skin biopsy will be required for diagnosis. Repeat testing or punch biopsy should be undertaken if initial PCR is negative and clinicians have a high clinical suspicion for M. ulcerans. The biopsy should be sent for histology, and fresh tissue should be sent for AFB staining, M. ulcerans PCR and mycobacterial culture.
  • In Victoria, please specify on the specimen request form that Buruli ulcer or M. ulcerans is suspected so that one swab is reserved for PCR testing by the Victorian Infectious Diseases Reference Laboratory (VIDRL) and not split for other laboratory testing such as culture.
    • PCR testing at VIDRL for Buruli ulcer can confirm diagnosis in a few days and is free for patients (a handling fee may still apply for private pathology collection services) ³⁾
    • General practitioners should include their patient’s Medicare details so that the test can be bulk billed. Public hospitals can also test for Buruli ulcer free of charge.
    • Under the Public Health and Wellbeing Regulations 2019, Buruli ulcer is a notifiable disease that must be notified within five days of diagnosis.

• rifampicin (adult and child) 10 mg/kg up to 600 mg orally, daily for 8 weeks, PLUS,
• clarithromycin 500 mg (child: 7.5 mg/kg up to 500 mg) orally, 12-hourly for 8 weeks
• if rifampicin cannot be taken then consider moxifloxacin in its place
• surgery may be needed.