The global burden of chromoblastomycosis

Abstract

Background: Chromoblastomycosis (CBM), represents one of the primary implantation mycoses caused by melanized fungi widely found in nature. It is characterized as a Neglected Tropical Disease (NTD) and mainly affects populations living in poverty with significant morbidity, including stigma and discrimination.

Methods and findings: In order to estimate the global burden of CBM, we retrospectively reviewed the published literature from 1914 to 2020. Over the 106-year period, a total of 7,740 patients with CBM were identified on all continents except Antarctica. Most of the cases were reported from South America (2,619 cases), followed by Africa (1,875 cases), Central America and Mexico (1,628 cases), Asia (1,390 cases), Oceania (168 cases), Europe (35 cases), and USA and Canada (25 cases). We described 4,022 (81.7%) male and 896 (18.3%) female patients, with the median age of 52.5 years. The average time between the onset of the first lesion and CBM diagnosis was 9.2 years (range between 1 month to 50 years). The main sites involved were the lower limbs (56.7%), followed by the upper limbs (19.9%), head and neck (2.9%), and trunk (2.4%). Itching and pain were reported by 21.5% and 11%, respectively. Malignant transformation was described in 22 cases. A total of 3,817 fungal isolates were cultured, being 3,089 (80.9%) Fonsecaea spp., 552 (14.5%) Cladophialophora spp., and 56 Phialophora spp. (1.5%).

Conclusions and significance: This review represents our current knowledge on the burden of CBM world-wide. The global incidence remains unclear and local epidemiological studies are required to improve these data, especially in Africa, Asia, and Latin America. The recognition of CBM as NTD emphasizes the need for public health efforts to promote support for all local governments interested in developing specific policies and actions for preventing, diagnosing and assisting patients.

Fig 1. Prevalence and absolute number of reported cases of chromoblastomycosis.

The world map was created, edited, and colored using the vector graphics editor Corel Draw X8. Public domain link to map base layer used in creating this figure:https://commons.wikimedia.org/wiki/File:BlankMap-World.svg.

Fig 2. The global distribution of chromoblastomycosis agents.

The world map was created, edited, and colored using the vector graphics editor Corel Draw X8. Public domain link to map base layer used in creating this figure:https://commons.wikimedia.org/wiki/File:BlankMap-World.svg.

Fig 3. The chromoblastomycosis lesion site.

A- The percentage of cases reported from a certain body site is shown. For lower limbs, lesions were described in 3,197 (56.7%) out of 5,639 patients; for upper limbs in 1,120 (19.9%) out of 5,634 patients; for the face and neck in 238 (4.3%) out of 5,555 patients; for the trunk in 180 (3.3%) out of 5,476 patients described; and finally for the buttocks in 89 (1.6%) out of 5,639 patients described. Unusual sites such as ear, breast, inguinal region were reported in 61 cases. B—Percentage of lesion severity.