Frequency and Genetic Characterization of Echinococcus granulosus in Paraffin‐Embedded Human Tissue Samples From the Northwest of Iran, West Azarbayjan

Objectives Cystic echinococcosis (CE), caused by the Echinococcus granulosus larval stage, poses health problems in the world, including Iran. This study is aimed at investigating the epidemiological and molecular characterization of E. granulosus collected from CE samples in Urmia, the northwest of Iran. Methods In this cross‐sectional study, the demographic information of 295 hydatid cyst patients who underwent surgery between 2010 and 2021 was recorded and analyzed statistically. Due to time and financial constraints, a total of 74 samples were evaluated. DNA of FFPE (formalin‐fixed paraffin‐embedded) hydatid cyst samples was extracted, and PCR was performed using mitochondrial genes cox1 and nad1. PCR products were electrophoresed and sequenced, and sequence analysis was performed using BioEdit and BLAST software. Results Among 295 cases studied, 173 (58.64%) were female and 122 (41.36%) male, respectively, and the CE frequency was significantly higher in patients aged 20–30 (n = 24/295; 8.1%), villagers (n = 70/295; 23.7%), and low educated cases (n = 82/295; 27.8%). The most group affected by CE was the housewives (n = 33/295; 11.2%), followed by the illiterate people (n = 82/295; 27.8%) and the farmers (n = 17/295; 5.8%). The liver (n = 52/295; 17.6%) and the lung (n = 40/295; 13.6%) were the most common sites for cyst formation, followed by the abdomen (n = 9/295; 3.1%), kidney (n = 4/295; 1.4%), thorax (n = 2/295; 0.7%), spleen (n = 2/295; 0.7%), and the pancreas (n = 3/295; 1.0%). DNAs from all 74 paraffinized hydatid cyst samples were extracted successfully. Of the whole FFPE samples amplified by PCR assay using nad1 and cox1 genes, only 27 and 25 FFPE samples were sequenced, respectively. The 9.1% (n = 27) for cox1 and the 8.4% (n = 25) for nad1 were sequenced. All samples′ analyses resulted G1. In addition, analysis of cox1 and nad1 genes did not identify any haplotypic variation. DNAs from all 74 paraffinized hydatid cyst samples were extracted successfully. Of the whole FFPE samples amplified by PCR assay using nad1 and cox1 genes, only 27 and 25 FFPE samples were sequenced, respectively. The 9.1% (n = 27) for cox1 and the 8.4% (n = 25) for nad1 were sequenced. All samples analyzed resulted G1. In addition, analysis of cox1 and nad1 genes did not identify any haplotypic variation. Conclusions Molecular findings identified the G1 genotype as the predominant genotype involved in E. granulosus transmission in the northwest region of Iran.