Investigating of Human Giardia intestinalis Assemblage in Markazi province, IRAN

Giardiasis is a worldwide infection of the small intestine. The causative agent of this disease is a flagellate protozoan called Giardia. It is only transmitted by mature cysts. It is important to identify the geographical distribution of Giardia intestinalis assemblages and genotypes in order to determine their transmission pattern in each region of the country. Therefore, the present study was performed to determine the predominant Giardia assemblage in human samples in Arak.

Fecal samples with severe contamination to Giardia were collected from laboratories affiliated to Arak University of Medical Sciences and Giardia cysts were isolated by flotation method and then DNA extraction was performed by phenol-chloroform method on these samples. The extraction product was used in the PCR reaction based on the identification of the β-giardin gene.  Finally, the product of PCR reaction was sent to the sequencing.

In this study, 25 samples of Giardia-infected feces were examined by PCR method and 12 of PCR reaction products were sent for sequencing. Ten isolates were 98% similarity to LC508640.1 sequence and two isolates were 97% similarity to JN616244.1. These isolates were recorded in GenBank (MT584765- MT584776). Results of current study showed assemblage A of Giardia intestinalis is the dominant in Arak.

The assemblage of all isolates that obtained from current study was matched with genotype A. Given that assemblage A is mostly contaminating humans and other mammals, it seems the transmission of Giardia is zoonotic in Arak city.