The global distribution of actinomycetoma and eumycetoma

Abstract

Background: Mycetoma, a chronic infection of the skin and underlying structures, affects those with a close relationship to the land, often in resource-poor areas of the world. Whether caused by any one of a variety of fungus or bacteria, mycetoma causes significant disability and mortality. Acknowledged as a neglected tropical disease (NTD) by the World Health Organization (WHO) in 2016, mycetoma is susceptible to being misunderstood, misdiagnosed, and mismanaged. In an effort to shift the balance in favor of recognition and effective treatment, sound epidemiological understanding is required.

Methods and findings: In this paper, a literature review of case reports and series (332 papers in total) is presented as three maps. We identified 19,494 cases dating from 1876 to 2019, with cases contracted in 102 countries. The first map shows where mycetoma has ever been reported, the second shows how many cases have been reported, and the third shows the ratio of eumycetoma (fungal) to actinomycetoma (bacterial). Most cases are found in Mexico, India, and Sudan, where mycetoma is studied rigorously. We identified emergence of new geographical loci, including the United States, Venezuela, Italy, China, and Australia. Notably, mycetoma is reported far outside the tropics. In the Americas, bacterial forms dominate, whereas, in Africa and Asia, the picture is more varied.

Conclusions: With better understanding of the epidemiology of mycetoma, more can be done to direct education, preventive measures, and treatment to at-risk areas, enabling a reduction in disease burden.

Fig 1. World distribution of mycetoma, 1984 adapted from Magana [24].

Fig 2. All the countries where autochthonous mycetoma has ever been reported.

Fig 3. The number of cases of mycetoma reported by country. Darker shades signify more cases.

Fig 4. Global map showing the ratio of actinomycetoma to eumycetoma per country, from reported cases.

The bluer colors indicate a higher percentage of eumycetoma, while pinker shades indicate more cases caused by bacterial species. White indicates that information was insufficient in the country (either because there were low numbers of reports or because the reports available did not contain adequate species data).