Global burden of human mycetoma: a systematic review and meta-analysis

Abstract

Mycetoma is a chronic infectious disease of the subcutaneous tissue with a high morbidity. This disease has been reported from countries between 30°N and 15°S since 1840 but the exact burden of disease is not known. It is currently unknown what the incidence, prevalence and the number of reported cases per year per country is. In order to estimate what the global burden of mycetoma is, a meta-analysis was performed. In total 50 studies were included, which resulted in a total of 8763 mycetoma cases. Most cases were found in men between 11 and 40 years of age. The foot was most commonly affected. Most cases were reported from Mexico, Sudan and India. Madurella mycetomatis was the most prevalent causative agent world-wide, followed by Actinomadura madurae, Streptomyces somaliensis, Actinomadura pelletieri, Nocardia brasiliensis and Nocardia asteroides. Although this study represents a first indication of the global burden on mycetoma, the actual burden is probably much higher. In this study only cases reported to literature could be used and most of these cases were found by searching archives from a single hospital in a single city of that country. By erecting (inter)national surveillance programs a more accurate estimation of the global burden on mycetoma can be obtained.

Figure 1. Flow diagram of literature search.

In this flow diagram it is shown that 258 titles and abstracts were screened initially. 50 papers were screened of which 17 were excluded due to failing the inclusion criteria, studies reported in two different studies, being reviews and 1 could not be retrieved. After manually searching the references of each of the retrieved papers, 17 more papers were identified and included in the analysis. This resulted in a total of 50 papers analysed.

Figure 2. Prevalence and the number of reported cases of mycetoma.

A: Average prevalence of mycetoma cases as calculated by the number of cases reported in a year in a certain country divided trough the total population of that country of that same year as reported by www.indexmundi.com/facts/indicators/SP.POP.TOTL/compare. B: the average number of mycetoma cases reported per year per country.

Figure 3. Age distribution of the mycetoma patients.

Age distribution as reported in 5240 cases of mycetoma. For the other 3523 cases no detailed information was available.

Figure 4. Mycetoma lesion site.

The mycetoma lesion site. In this figure the percentage of cases reported from a certain body site is shown. For 2.6% of the cases the lesion site was unknown to the authors and 1.0% of the patients had multiple lesions. The percentages shown in this figure were calculated from data obtained from 4581 cases. For the other 4182 cases no detailed information was available.

Figure 5. Distribution of the most common causative agents per country.

The distribution of Madurella mycetomatis, Actinomadura madurae, Streptomyces somaliensis, Actinomadura pelletieril, Nocardia brasiliensis and Nocardia asteroids per country. For each country the number (N) of species identified is given. The percentage of Madurella mycetomatis, Actinomadura madurae, Streptomyces somaliensis, Actinomadura pelletieril, Nocardia brasiliensis and Nocardia asteroids were calculated from these data and displayed in the corresponding panels.

Figure 6. India.

Average number of mycetoma cases reported per year in India per state and the causative agents per state.