World Health Organization in 2018. Most countries do not report data on Buruli ulcer to the World Health Organization, and the extent of its spread is unknown. In many endemic countries, health systems likely do not record each case due to insufficient reach and resources, and so the reported numbers probably underestimate the true prevalence of the disease. Buruli ulcer is concentrated in West Africa and coastal Australia, with occasional cases in Japan, Papua New Guinea and the Americas. In West Africa, the disease is predominantly reported from remote, rural communities in Benin, Côte d'Ivoire, Cameroon, and Ghana. Other countries in the region also have Buruli ulcer to some degree; a 2019 systematic review of prevalence studies found a clear consensus that it is present in the Democratic Republic of the Congo, Gabon, Liberia, Nigeria, Togo, and South Sudan, as well as "strong" or "very strong" evidence of the disease in the Republic of the Congo, Sierra Leone, the Central African Republic, Guinea, and Uganda. Buruli ulcer is regularly reported from Australia, where it occurs in coastal clusters—two in Queensland (near Rockhampton and north of Cairns) and two in Victoria (near Bairnsdale and Melbourne). It is more rarely reported from Japan, Papua New Guinea, and the Americas. Japan reports a few locally acquired cases per year scattered across the main island, Honshu. Papua New Guinea sporadically reports cases to the World Health Organization, typically less than a dozen per year. In the Americas, most Buruli ulcer is reported from French Guiana, with few cases described in surrounding countries. A 2019 review found "strong" evidence for the presence of Buruli ulcer in French Guiana and Peru, and "moderate" evidence in Brazil, Mexico and Suriname. Within affected countries, Buruli ulcer tends to occur in rural areas near slow-moving or stagnant water. In particular, the disease tends to appear near water that has experienced human intervention, such as the building of dams or irrigation systems, flooding, or deforestation. Within endemic communities, few characteristics predict who will acquire Buruli ulcer. Males and females are equally likely to be infected. Ulcers can appear in people of all ages, although infections are most common among children between 5 and 15 years in West Africa, and adults over 40 in Australia and Japan. Other animals M. ulcerans infection can cause Buruli ulcer-like lesions in some non-human animals. Natural non-human infections have only been described in coastal Victoria,