Genetic diversity of Leishmania tropica strains isolated from clinical forms of cutaneous leishmaniasis in rural districts of Herat province, Western Afghanistan, based on ITS1-rDNA.

Despite the high incidence of cutaneous leishmaniasis (CL) in Afghanistan, there is a little information concerning epidemiological status of the disease and phylogenetic relationship and population structure of causative agents. This study was conducted to determine the prevalence and distribution of CL cases and investigate the Leishmania tropica population structure in rural districts of Heart province in the West of Afghanistan in comparison to neighboring foci. Overall, 4189 clinically suspected CL cases from 177 villages (including 12 districts) in Herat province were enrolled in the referral laboratory of WHO sub-office in Herat city from January 2012 to December 2013. 3861 cases were confirmed as CL by microscopic examination of Giemsa-stained slides. ITS1 PCR-RFLP analysis showed dominance of L. tropica (more than 98%) among 127 randomly chosen samples. Analysis of the ITS1 sequences revealed 4 sequence types among the 21 L. tropica isolates. Comparison of sequence types from Herat rural districts with the representatives of L. tropica from Iran, India, and Herat city showed two main population groups (cluster A and B). All isolates from Herat province, India and Southeast, East, and Central Iran were found exclusively in cluster A. The close proximity of West Afghanistan focus and Birjand county as the capital of Southern Khorasan province in East Iran can explain relatively equal to the genetic composition of L. tropica in these two neighboring regions. In addition, two populations were found among L. tropica isolates from Herat rural districts. Main population showed more similarity to some isolates from Birjand county in East Iran while minor population probably originated from the Southeast and East Iranian L. tropica. Recent study provided valuable information concerning the population structure of L. tropica and epidemiology of ACL in the West of Afghanistan, which could be the basis for molecular epidemiology studies in other regions of Afghanistan.