Molecular identification of Leishmania species causing cutaneous leishmaniasis in Mashhad, Iran

Introduction and objective: Cutaneous leishmaniasis (CL) is considered as an important health problem in many parts of Iran especially in Mashhad, north-eastern part of Iran. Various species of Leishmania cause the disease. Identification of Leishmania parasites is useful for control and preventive plans. Although epidemiological and clinical findings are necessary but they are not sufficient for identification of causative agents of CL. In order to identify Leishmania spp. a definite molecular technique, Polymerase Chain Reaction (PCR) method was used over a 12 months period.

Materials and methods: A total of twenty-one patients participated. Direct smear and culture in modified NNN medium followed by sub-culture in RPMI-1640 were performed for each case. Genomic DNA was extracted by using proteinase k and amplified by specific primers of kDNA. The PCR product was analysed by gel electrophoresis using 2% agarose. Gel staining was performed by ethidium bromide. The presence of 620bp fragment indicated Leishmania major and 800bp indicated L. tropica.

Results: Of 21 positive cultures out of 53 positive samples, nineteen isolates were identified as L. tropica and two others were identified as L. major. However, by previous investigations, Mashhad was known, as an endemic focus for Anthroponotic Cutaneous Leishmaniasis (ACL), but it is now concluded that both ACL and Zoonotic Cutaneous Leishmaniasis (ZCL) are present in Mashhad and L. tropica is the dominant species.

Conclusion: Both L. tropica and L. major are the causative agents of cutaneous leishmaniasis in Mashhad. L. tropica is the dominant Leishmania species in Mashhad. However PCR technique is a very reliable method to detect Leishmania DNA, but it is not easy to obtain Leishmania culture samples.