Mycobacterium ulcerans in the Daintree 2009-2015 and the mini-epidemic of 2011

Abstract

BACKGROUND: Mycobacterium ulcerans infection (Buruli ulcer) is the third most common mycobacterial disease in humans, with presentations ranging from self-limiting skin nodules and ulcers to aggressive infiltrative infections with extensive oedema, fat and skin necrosis. The two foci in Australia are in Victoria and Far North Queensland. We present the 2009-2015 case series for the Queensland focus with special reference to the 2011 spike of 64 cases. METHODS: This case series is based on a combination of prospectively and retrospectively collected data on 95 confirmed cases of M. ulcerans between 2009 and 2015 from the endemic area, consisting of 88 Category 1 lesions (single lesion less than 5 cm), three Category 2 (5-15 cm plaques) and four Category 3 (one multiple lesions, three oedematous infection). RESULTS: Eighty-nine patients underwent surgery. Thirty-two patients received antibiotics. Management details for three patients were unavailable. Recurrent disease was identified in six patients (6%). CONCLUSION: Mycobacterium ulcerans infection (Buruli ulcer) is an endemic but uncommon infection in Far North Queensland with usually fewer than 10 cases per year. Small ulcers predominate. Most were excised and antibiotic treatment was frequently adjuvant rather than therapeutic. The 64 cases in 2011 was unexpected, not duplicated subsequently, and may relate to local climatic variations. Local awareness of the disease facilitated early presentation and diagnosis in most cases, enabling timely treatment while lesions were small and easily managed.