Abstract
Background: Cystic echinococcosis (CE) is a parasitic infection that’s caused by the larval form of Echinococcus granulosus (a member of the Taeniidae family). The infection is spread by fecal-oral contact, with infected domestic dogs. CE threatens human health and destroys animal production all over the world. Echinococcus granulosus genotypes need to be correctly identified for better control and prevention.
Aim: This study was done to isolate the genotypes of E. granulosus from human, sheep, and cattle samples in Iraq, by molecular and phylogenetic methods.
Methods: Thirty-hydatid cyst samples were collected: 10 from human patients in hospital and 20 from sheep and cattle slaughtered in Al-Diwaniyah province. PCR amplification of the mitochondrial Cox1 gene was conducted. The amplified products were sequenced and phylogenetically studied.
Results: The findings showed three genotypes of E. granulosus (G1, G2, and G3). G1 was more common in human isolates (98.40–99.70% homology), G1 and G2 were also found in sheep (98.34–99.70% homology), and G1 and G3 in cattle (98.40–99.75% homology). Phylogenetic analysis identified a clear clustering of genotypes that belonged to the same host. G1 genotype is the most common strain that infects people, sheep and cattle in Iraq, and it is highly zoonotic and economic.
Conclusion: These data are useful for molecular epidemiological research on E. granulosus in Iraq and to aid disease control efforts.

Key words: Cattle, Echinococcus granulosus, genotype, human, Iraq, sheep