Chromoblastomycosis and sporotrichosis in Madagascar : Epidemiology, molecular diagnostic and perspectives

Chromoblastomycosis (CBM) and sporotrichosis (SP) are endemic mycosis in Madagascar that occurred following injury and telluric contamination. CBM is mostly due to Fonsecaea pedrosoi or Cladophialophora carrionii and affects usually the subcutaneous tissue, whereas SP is caused by Sporothrix schenckii by invading the lymphatic system of the arms and legs. These fungal infections are considered neglected diseases because of poor resources allocated to their diagnosis, monitoring or prevention. The general objective was to assess the current prevalence of these mycosis in Madagascar. The specific objectives were to characterize the causative fungal species and their habitat in order to prevent contamination, and to set up a sustainable clinical and laboratory network to allow proper case management and to provide a molecular-based species identification. The study comprised a prospective clinical study that started in March 2013. Patients were recruited during field investigations and consultations provided in a dermatology department. Pus, biopsy and squamous were sampled from the lesions. Informed consent from the patients and ethical approval from the Ministry of Health were obtained. Histopathological and mycological analysis (direct examination and culture on Sabouraud-Cycloheximide) were performed. We have developed a PCR-based strategy that was validated on reference strains provided by BCCM/IHEM (Belgian Coordinated Collections of Micro organism). First, two sets of universal primers (NL-1/NL4 and ITS5/ITS4) were used to confirm the fungal origin of the lesions. Then, specific primers (SSHF31/SSHR97, Fon-F/Fon-R, EdF/EdR) were used for fungal species identification. Ninety two patients were enrolled. Mean age was 38.7 years and men were predominant with 71.7 % of cases. Overall, 47.8 % were farmers, 30.4 % self-employed, 12.0 % students and 9.8 % unemployed. Clinically, 32.6 % of cases were suspected having CBM and presented with crusted, verrucous and tumoral lesions ; 34.8 % of cases were suspected having SP characterized mainly by ulcerative and nodular lesions of the lymphatic system of the lower limbs. Mycological analysis confirmed 33 cases of SP and 13 cases of CBM. The molecular diagnosis confirmed 34 Sporothrix sp, leading to a SP prevalence of 37 % and 1 Cladophialophora sp and 16 Fonsecaea sp leading to a CBM prevalence of 18.5 %. One mycetoma probably of bacterial origin was also diagnosed. CBM cases were predominant in the north-east, ea