Your Guide to
Neglected Tropical Diseases

Buruli ulcer is a chronic skin disease caused by Mycobacterium ulcerans, a type of bacteria (germs) that lives in aquatic environments. The disease occurs in tropical, subtropical, and some temperate regions, and typically begins as painless lumps or swelling on the limbs. Without early treatment, it progresses to large, painless ulcers that can destroy skin and soft tissue, affecting bones and causing permanent disfigurement and disability.

The disease causes significant stigma, lost income opportunities, and socioeconomic burden. Early detection and antibiotic treatment can cure most cases, but delayed treatment leads to scarring, muscle and joint deformities, and long-term disability.

The mode of transmission remains unknown. Mycobacterium ulcerans is found in slow-moving or stagnant water and has been detected in aquatic insects, mosquitoes, fish, biofilms, and water itself. Potential modes of transmission includes direct entry through cuts and wounds from contaminated water or soil or bites from infected aquatic insects or mosquitoes. Research has shown that the bacteria thrive in freshwater ecosystems and can multiply in the salivary glands of certain water bugs. However, field studies have not confirmed these insects as primary vectors.

Human-to-human transmission is highly unlikely. The bacteria produce a toxin that destroys tissue, suppresses the immune system at the infection site, and causes painless progression, making early detection difficult.

Geographic scope:

• Reported in more than 30 countries across Africa, the Americas, Asia, and the Western Pacific.
• Over 80% of all cases worldwide have been reported from Africa, and most cases occur in West and Central Africa (Benin, Cameroon, Côte d'Ivoire, Democratic Republic of Congo, Ghana, Nigeria).
• Also endemic in Australia and Papua New Guinea; Japan reports sporadic cases of a local subspecies.

Population affected:

• More than 1,800 suspected cases reported globally each year, representing a notable decline from around 5,000 cases per year in 2010 and earlier.
• However, the true burden is likely higher due to under-reporting, limited healthcare access, and misdiagnosis.
• Nearly 50% of African cases occur in children under the age of 15.

WHO recommends an 8-week course of rifampicin and clarithromycin, two oral antibiotics that replaced earlier painful injections. Antibiotics kill the bacteria and reverse immune suppression. Early detection cures approximately 80% of cases without surgery. Healing is slow: 6 months to over 2 years depending on ulcer size. Wound care is essential, and large ulcers may require surgery for tissue removal or skin grafts.

Risk reduction includes wearing long-sleeved shirts and pants near water, using insect repellent, immediately washing and covering cuts, and avoiding slow-moving or stagnant water in endemic areas. No vaccine exists, although BCG provides temporary partial protection.

※Animals can sometimes act as hosts. In Australia, possums are known to carry the bacteria.