The third edition of Tropical Infectious Diseases describes Mycobacterium ulcerans infection – otherwise known as the Buruli ulcer – as a “necrotizing infection of the skin, subcutaneous tissue, and bone”. If this flesh-eating microbe doesn’t sound at all pleasant, then you’d be right, which is why medical professionals are worried about a new, unexplained outbreak in part of Australia.
Writing in the Medical Journal of Australia, a team led by Barwon Health explains how the infection is normally found in the tropical regions of West or Central Africa. Every year, around 2,000 new cases of the disease are diagnosed, which affects all age groups and can lead to long-term disability, cosmetic deformity, and severe emotional and psychological trauma.
Once it infects its host, M. ulcerans – belonging to the same genus as leprosy and tuberculosis – produces a unique toxin which both causes tissue damage and inhibits the immune system’s ability to deal with it. Although it can be treated with powerful (side-effect prone) antibiotics, particularly damaging infections can require reparative plastic surgery.
Recently, however, the authors explain that there’s been a “worsening epidemic, defined by cases rapidly increasing in number” in southeastern Victoria, a temperate part of the country. In 2016, there were 182 new cases, the highest ever reported. In 2017, up to mid-November, there were a further 236 cases.
Although the disease has been acknowledged to exist in the state since 1948, very little progress has been made in curtailing the bacterium simply because we actually know very little about it.
The team emphasizes that “efforts to control the disease have been severely hampered because the environmental reservoir and mode of transmission to humans remain unknown.” This uncertainty is epitomized by the World Health Organization (WHO), which notes that the type of people that are infected, and the fact the disease specifically manifests itself in a case-by-case way, “[varies] considerably within and across different countries and settings.”