Epidemiological aspects of mycetoma from a retrospective study of 264 cases in West Bengal

Between 1981 and 2000, 264 cases of mycetoma were diagnosed clinically and microbiologically at Calcutta School of Tropical Medicine. Retrospective analysis of the records revealed that the ratio of actinomycetomas and eumycetomas was 197 : 67; the male to female ratio was 183 : 81. Ninety-four cases occurred in the 1980s and 170 in 1990s, with significantly more infections of Actinomadura spp. (P < 0.01) and fewer with Nocardia caviae (P < 0.01) during the last decade. Pricking was the most common injury associated with eumycetomas (P < 0.01). A total of 196 infections were in exposed body parts and 68 in covered areas. The localization of mycetomas differed significantly (P < 0.01) according to sex, incidence of actinomycetomas or eumycetomas, and obvious history of trauma. Exposed area cases were more common among agricultural workers (P < 0.01), while covered area mycetomas were almost always actinomycetomas with a remarkably lower incidence of N. caviae, A. madurae and Madurella grisea infections. The peak age of onset was between 16 and 25 years. The delay of diagnosis for the 80th percentile of cases was around 6 years for cases caused by N. brasiliensis and Streptomyces spp.; 8 years for N. caviae and N. asteroides; and 10 years for M. grisea and Actinomadura spp. From the history of trauma in 130 patients, the 80th percentile incubation period (IP) was calculated for N. brasiliensis, N. caviae and N. asteroides as 3 years; for Actinomadura spp. 7 years and for M. grisea 9 years. The minimum IP for all organisms was around 3 months.