Expansion of urban cutaneous leishmaniasis into rural areas of southeastern Iran: Clinical, epidemiological and phylogenetic profiles explored using 7SL high resolution melting-PCR analysis.

Abstract

Cutaneous leishmaniasis (CL) has increased remarkably in Iran and has expanded into new areas. The present study aimed to assess the emerging CL outbreak in southeastern Iran using high resolution melting-polymerase chain reaction (HRM-PCR) and phylogenetic analysis using the 7SL RNA gene marker. A cross-sectional and analytical survey was conducted during a house-to-house census of 11,021 inhabitants in Narmashir County in southeastern Iran in 2016. The cases were detected by direct smear microscopic examination and sequencing and were characterized using the 7SL RNA gene. All age groups and sexes were equally affected. Most were single lesions (70.7%). The hands (55.2%) and face (37.9%) were the main sites of involvement. The disease was more common among illiterate persons. Sequencing and HRM-PCR revealed that Leishmania tropica (accession no. MH632168 Qale-Shahid) was the principal causative agent of anthroponotic CL (ACL) in new areas of expansion. This is the first emergence of ACL in rural areas of Narmashir County. Based on the molecular data, the causative parasite species confirmed to be L. tropica. Sequencing and phylogenetic analysis indicated that a single clone of the organism derived from a single source has spread into the affected villages. Construction of a main road, population movement and recent urbanization in the area are likely the major factors associated with the establishment of this new outbreak. This study was essential to enable the planning of effective therapeutic and prophylactic measures to control the disease.