This is the first in a series of posts about the 17 WHO-recognized Neglected Tropical Diseases (NTDs). Although that number has risen to 18 as of about a month ago when the 69th World Health Assembly passed a resolution naming mycetoma as a neglected tropical disease.
But back to Buruli ulcer, the topic of the day. Buruli ulcer was first described by Sir Albert Cook in patients from Buruli County, Uganda. Buruli ulcer is a bit of a tricky NTD, as the route of transmission is unknown. Cases do commonly occur near bodies of water such as slow-moving rivers, ponds, lakes, swamps but no agent of transmission has been identified. We do know that it’s caused by a bacterium, Mycobacterium ulcerans, which results in a debilitating skin and soft tissue disease that can cause permanent disfigurement and disability.
Buruli ulcer mostly affects children under 15 years of age and in 2014 there were 2200 new cases in 12 of the 33 countries where Buruli ulcer has been reported (not all countries report cases to the WHO so the case count is likely higher). The majority of cases are reported in West and Central Africa and it is well-known in Austrailia. Except for a few countries, the case count has been declining since 2005 but no one knows why exactly.
While Buruli ulcer may result in permanent disability and disfigurement if not promptly diagnosed and treated, 80% of cases detected early can be cured with a combination of antibiotics. However, even with prompt diagnosis and treatment, patients can still experience cosmetically disfiguring scars. The disease severity has been separated into three categories, from a small lesion to systemic dissemination. Mycobacterium ulcerans, the causative agent of Buruli ulcer, releases a unique toxin called mycolactone which inhibits the host’s immune response and makes the lesions painless. This toxin allows the disease to progress without pain or fever which means that unless the affected person sees the lesion they may not catch it in the early stages. Additionally, with the immunosuppresive function of the toxin, the body’s immune system doesn’t launch an attack to destroy the bacteria.
There is hope for the future. Research is being done to develop an oral antibiotic to treat Buruli ulcer and work is being done to develop a point-of-care test so diagnoses can be made on the spot instead of samples being sent to one of 17 laboratories capable of diagnosing Buruli ulcer.
If you’d like to learn a little bit more about Buruli ulcer, I highly recommend these two videos, Buruli ulcer: from a difficult past to a hopeful future and Buruli ulcer: Progress and hope (this one is about 30 minutes).