[Epidemiology of Cutaneous Leishmaniasis in Algeria through Molecular Characterization]

Three distinct noso-epidemiological cutaneous leishmaniasis (LC) entities coexist in Algeria: the so-called sporadic form of the North (LCN), the zoonotic form (LCZ) and the chronic form (LCC). The precise identification of the parasitic species involved in each of the forms makes it possible to specify the geographical distribution of each of the forms raised, to distinguish their clinical aspects, to guide the therapeutic behaviors and to adapt the control programs. Ninety-seven (97) human strains from 97 cases of LC were subjected to molecular characterization by PCR-ITS1 followed by sequencing of this inter-gene space. Our results confirm the endemicity of the three forms. The LCN, caused by L. infantum (17 isolates/97 i.e. 17.52%) is limited to the North of the country mainly (16 isolates/17). Its geographical distribution is superimposable to that of visceral leishmaniasis with an extension more and more reported in previously unaffected areas, such as the regions of Tlemcen and Oran in the West, Setif, Annaba and Collo in the East. The LCZ, due to L. major (70 strains/97 i.e. 72.16%), remains the dominant form in the arid and semi-arid zones (47 strains/70) with a progression towards the North (20/70 strains). Indeed, long confined to the Sahara, it shows a geographical extension outside its historic homes of Biskra and Abadla. This form is progressing dangerously towards the highlands and the steppe regions of the country. The most interesting fact was the identification of L. tropica for the first time in North-Central and North-West Algeria in Algerian patients who had never left the national territory. Out of the 10 strains of L. tropica identified, 8 belonged to patients of Syrian origin and 2 to Algerian patients. L. tropica was reported for the first time in 2008 in 6 patients living in Constantine (North-East Algeria) and in 2017, still in the North-East of the country, in Annaba. The observation of L. tropica in the North and Northeast center of the country, where L. infantum and L. major coexist, suggests changes in the epidemiology of cutaneous leishmaniasis in Algeria, which highlights the interest of more investigations to better understand the transmission cycle of the different entities.