A necrotising skin disease found in pockets of Australia has puzzled scientists for decades, and while the diagnostics and treatment for Buruli ulcer are clear-cut and highly effective, its spread continues to remain a mystery.

Last week, health authorities issued an alert for a major outbreak in Victoria, with 266 cases so far this year extending into new geographical areas.

The state is one of the most commonly affected regions globally, with annual incidence rising since the mid-1990s.

Australia is also the only developed country to report significant local transmission of the disease-causing Mycobacterium ulcerans.