Genetic Characterization of Echinococcus granulosus from a Large Number of Formalin-Fixed, Paraffin-Embedded Tissue Samples of Human Isolates in Iran

Abstract

Abstract. Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, presents an important medical and veterinary problem globally, including that in Iran. Different genotypes of E. granulosus have been reported from human isolates worldwide. This study identifies the genotype of the parasite responsible for human hydatidosis in three provinces of Iran using formalin-fixed paraffin-embedded tissue samples. In this study, 200 formalin-fixed paraffin-embedded tissue samples from human CE cases were collected from Alborz, Tehran, and Kerman provinces. Polymerase chain reaction amplification and sequencing of the partial mitochondrial cytochrome c oxidase subunit 1 gene were performed for genetic characterization of the samples. Phylogenetic analysis of the isolates from this study and reference sequences of different genotypes was done using a maximum likelihood method. In total, 54.4%, 0.8%, 1%, and 40.8% of the samples were identified as the G1, G2, G3, and G6 genotypes, respectively. The findings of the current study confirm the G1 genotype (sheep strain) to be the most prevalent genotype involved in human CE cases in Iran and indicates the high prevalence of the G6 genotype with a high infectivity for humans. Furthermore, this study illustrates the first documented human CE case in Iran infected with the G2 genotype.

Global Distribution of Alveolar and Cystic Echinococcosis

“…Table 10 summarizes the occurrence of Echinococcus species and genotypes causing CE in the ME. Echinococcus granulosus (G1eG3) is the dominant species responsible for most human and animal infections (Harandi et al, 2002;Al-Qaoud et al, 2003;Utuk et al, 2008;Vural et al, 2008;Sharbatkhori et al, 2009), with E. intermedius (G6, camel strain) as the second most prevalent species in the region and increasingly recognized in human cases (Rostami et al, 2015;Al Kitani et al, 2015). In addition there have been reports of the occurrence of E. intermedius (G7) in Turkey and Iran Eryildiz and Sakru, 2012;Fadakar et al, 2015).…”

New mitogenome and nuclear evidence on the phylogeny and taxonomy of the highly zoonotic tapeworm Echinococcus granulosus sensu stricto

“…Echinococcus granulosus s. s. (genotypes G1-G3) is spread globally among wild and domestic animals, with highly endemic foci in South America, the Mediterranean basin and Central Asia (Dakkak et al 2010;Hajialilo et al 2012;Rostami et al 2015;Boufana et al 2015;Zhang et al 2015;Cusher et al 2016;Laurimäe et al 2016). E. granulosus s. s. is also the most frequently implicated Echinococcus species in human infections, 88% worldwide, according to a recent estimate by Alvarez Rojas et al (2014), therefore deserving particularly close attention.…”

Echinococcus granulosus genotypes in Iran: a systematic review

“…;Pestechian et al, 2014;Sharafi et al, 2014;Vahedi et al, 2014;Fadakar et al, 2015;Farhadi et al, 2015;Rostami et al, 2015;Spotin et al, 2015;Oskouei et al, 2016;Maldonado et al, 2017 …”