The Molecular Epidemiology of Crithidia Strains in Isfahan City and Surrounding Areas, Iran

Background: Genotyping of Crithidia species is of high importance in the selection of an appropriate method to control and prevent cutaneous leishmaniasis (CL), determination of the best therapeutic effect of drugs, and preparation and evaluation of the vaccines. Methods: In order to identify the strains of Crithidia, sampling was done in one of the endemic regions of wet or rural type zoonotic cutaneous leishmaniasis (ZCL) in Isfahan city and surrounding areas, Iran. Samples were 602 patients with wet cutaneous leishmaniasis referred to Isfahan Leishmaniasis Research Center or other health centers in the vicinity of Isfahan. Sampling in Novy-MacNeal-Nicolle medium (NNN) medium, extraction of DNA from promastigotes, implementation of the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, amplification of internal transcribed spacer (ITS1), and application of HaeIII enzyme were performed. Findings: 201 patients (33.39%) were found with two species of Crithidia, 27 cases of Crithidia fasciculata (13.44%) and 11 cases of Crithidia luciliae (5.47%). The rest of the cases, however, were trypanosomatidae with accession number of GQ331988; molecular analysis showed 92% had tendency of homology with Crithidia fasciculata and 89% with Crithidia luciliae (163 cases or 81.9%). Out of 351 patients (58.31%), leishmaniasis parasite was isolated, and out of 50 patients (8.31%), neither Leishmania nor Crithidia were isolated; therefore, their report was negative following cultured samples. Conclusion: The results of the present study suggested that Crithidia not only contaminates leishmania culture but also enjoys genetic polymorphism in Isfahan and surrounding areas.