Molecular diagnosis of the first cases of Leishmania tropica cutaneous leishmaniasis in elementary school pupils in the Tchiamba-Nzassi health district in Pointe Noire, Republic of Congo

Introduction: Leishmaniasis is a neglected tropical disease caused by a flagellate parasite of the genus Leishmania transmitted to humans by the bite of a sandfly. General objective: To contribute to the molecular diagnosis of cutaneous leishmaniasis in a population of elementary school pupils in the Tchiamba-Nzassi health district with suspicious chronic lesions in the Pointe-Noire department. Methodology: This was a descriptive cross-sectional study including 23 suspected cases of cutaneous leishmaniasis among elementary school pupils in the DS of Tchiamba-Nzassi in the department of Pointe-Noire, which took place from June to November 2022, a period of 06 months. Sociodemographic characteristics (age, sex) were collected using a survey form. Two diagnostic methods were used to detect Leishmania: Parasitological examination of MGG-stained smears and molecular diagnosis, which involved amplifying Leishmania DNA in lesion secretions by real-time PCR using the TECHNE "Pro qPCR Reagents Leishmania" kit. Results: A total of 23 patients were studied. The mean age of our subjects was 11.7 ± 2 years, with extremes ranging from 8 to 15 years. Males were predominantly represented (67%), with a sex ratio (2H/1F) of 2. Parasitological diagnosis did not reveal the amastigote form of leishmaniasis on the slides. Molecular analysis revealed Leishmania DNA in three (3) samples, i.e., 13% of the study population. The lesions in which L. tropica was detected were the legs (2 cases) and the toe (1 case). Conclusion: The incidence of cutaneous leishmaniasis was low in our study. This pathology affected children of all ages with chronic skin lesions located preferentially on the lower limbs. Molecular biology was used to diagnose this neglected tropical disease and the species identified was Leishmania tropica.