Buruli ulcer is a disease caused by a bacteria(Mycobacterium ulcerans) related to tuberculosis and leprosy. It is not certain what causes the disease. Occurences happen around slow moving ponds and rivers, in rural farming communities.
The disease starts as a painless, mobile swelling in the skin called a nodule. It progresses with no pain. If not caught on time disfiguring ulcers or sores on the skin can develop. Bones can be affected causing gross deformities. Even after being cured, joint movement maybe impaired.
World Health Organization.Buruli ulcer disease <http://www.who.int/mediacentre/factsheets/fs199/en/>