Molecular Identification of Giardia intestinalis and Blastocystis hominis Genotypes from Fecal Samples in Khuzestan Province, Iran

Background and purpose: Giardia and Blastocystis are common parasites of humans with a wide range of hosts. The aim of this study was to identify the genotypes of Giardia intestinalis and Blastocystis hominis in individuals attending Bavi health centers in Khuzestan province, Iran. Materials and methods: In this study, 30 positive stool samples of Giardia and Blastocystis were collected from individuals attending Bavi health centers in 2019-2020. Then DNA extraction was performed on fecal samples. PCR was performed using GDH gene for Giardia and 18S rRNA region for Blastocystis and PCR products were drawn to determine sequence type and phylogenetic tree. Results: Sequence analysis was performed on PCR products from Giardia based on amplification of GDH gene. Based on the results of DNA sequence, all identified samples belonged to assemblage BIV. Sequence analysis was performed on PCR products from Blastocystis according to amplification of 18S rRNA gene and all identified samples belonged to ST3 subtype. Conclusion: The study showed that the predominant genotype of Giardia in Bavi was BIV which indicates a zoonotic cycle in this region. In addition, the predominant subtype of blastocystis was previously reported in this region (ST3) often seen in human-to-human transmission cycle, although there have been reports of animal-to-human cycle. Therefore, alongside health measures to control these two parasites in this area, molecular epidemiology studies in local animals is necessary to determine the zoonotic transmission of Giardia and Blastocystis parasites in this region.