Buruli ulcer (BU) is a disease of the skin and soft tissue caused by Mycobacterium ulcerans. Although BU occurs in over 30 countries worldwide, predominantly in tropical West Africa, Australia is the only developed country to report significant local transmission. Since its first description in Gippsland in 1948, BU has been reported in Phillip Island; the Mornington and Bellarine Peninsulas; and the south-eastern bayside and inner northern metropolitan suburbs of Melbourne. There is also an established focus of disease in Far North Queensland. Sporadic cases have been reported in the NT and Capricorn Coast of southern Queensland. Single cases have occurred in WA and NSW.
BU often begins as a painless nodule or papule on the skin, usually on the upper and lower limbs. Over a period of weeks to months, the disease slowly progresses with the skin around the papule breaking down to cause an ulcer. Left untreated, the disease can cause extensive tissue damage that, in severe cases, can leave patients with significant morbidity and disability. Fortunately, most cases in Australia are diagnosed early and can be successfully treated with an 8 week oral antibiotic regimen comprising rifampicin with either clarithromycin or a fluoroquinolone.
Unlike most mycobacterial diseases where culture remains the diagnostic gold standard, PCR is the preferred method for laboratory diagnosis of BU. When performed on a dedicated, good quality specimen, PCR is highly sensitive and specific and results are available within days. Culture for M. ulcerans is less sensitive and usually takes 8-12 weeks; however, culture is still important for clinical management of disease and for molecular epidemiological studies.
The mode of transmission and environmental reservoir have not been fully elucidated. However, evidence from case-control, epidemiological and laboratory studies, combined with environmental testing for M. ulcerans, strongly suggests that infection occurs when bacteria from contaminated environments enter a break in the skin caused by some form of trauma, including insect bites. There is no evidence of human-to-human transmission.
This talk will review BU history, epidemiology, clinical aspects, laboratory diagnosis and research on the mode of transmission/environmental reservoir.