Echinococcus granulosus sensu stricto in Livestock and Hu-man in Hamadan, Western Iran

Background: Cystic echinococcosis, a major public health and economic concern, is a zoonotic helminth infection with worldwide distribution. This study was conducted to investigate the genetic characteristics of hydatid cysts isolated from human and livestock in Hamadan region, western Iran during 2016-2017. Methods: Ten human hydatid cysts and 40 animal hydatid cysts including 32 sheep, 5 cattle and 3 goats were genotyped by PCR amplification of two mitochondrial genes, cox1 and nad1. Genetic identification of the isolates was performed by using bioinformatics software and mtDNA nucleotide sequences of the parasite, available in GenBank database. Results: The PCR amplification was successfully carried out on 50 hydatid cyst isolates and then the nucleotide sequencing was conducted. The sequence analysis of the samples found that the isolates belonged to E. granulosus sensu stricto including G1 (42/50, 84%), G2 (4/50, 8%) and G3 (4/50, 8%) genotype. The G1 genotype was detected in human (8/10, 80%), sheep (26/32, 81%), cattle (5/5, 100%) and goat (3/3, 100%) hydatid cysts. The G2 and G3 genotypes were found only in sheep and human isolates. Alignment analysis of the cox1 and nad1 gene sequences revealed thirteen and ten sequence types, respectively. Conclusion: G1 was the prevailing genotype of E. granulosus in the area and dog-sheep transmission cycle should be considered when implementing hydatidosis control programs. In addition, high genetic diversity was detected among the hydatid cyst isolates.