A DNA-Based Identification of Strongyloides stercor alis Isolates from Iran

Abstract: Strongyloides stercoralis, the etiological agent of strongyloidiasis, is one of the most common parasitic nema­tode with the unique ability to complete its life cycle and proliferate within the host. Although it is an endemic parasite in Iran, no molecular characterization is available on isolates originated from the country. Therefore, this study was con­ducted for molecular identification of human Strongyloides isolates in the three most prevalent provinces. After microscopical examination and agar plate culture of nearly 1500 stool samples, 20 isolates of S. stercoralis filari­form larvae were recovered from (Gilan and Mazandaran in north and Khouzestan in south) of Iran. The genomic DNA was extracted from all these samples and two primer sets were selected for amplification. ITS1 region of the rDNA gene was amplified by a nested Polymerase Chain Reaction (nested-PCR). The PCR prod­ucts were sequenced and analyzed in compari­son with the sequences deposited in GenBank. DNA sequence analysis of ITS1 region showed that all the 20 isolates were S. stercoralis. There was slight varia­tion in the ITS1 region among the isolates. ITS1 sequencing seems to be a valid target for molecular identification of S. stercoralis.