Occurrence and genetic characterization of Echinococcus granulosus in naturally infected adult sheep and cattle in Romania

An epidemiological and molecular study was conducted to investigate the occurrence and genetic diversity of Echinococcus granulosus isolates from adult sheep and cattle in Romania. Overall, 642 sheep (aged over 3 years) and 1878 cattle (aged over 5 years) from 16 counties were examined for hydatid cysts. Of them, 421 (65.6%) sheep and 754 (40.1%) cattle were found infected by cystic echinococcosis (CE). Germinal layers were collected from 98 individual cysts (one cyst per animal; 31 from sheep and 67 from cattle), DNA was extracted and two different mitochondrial DNA genes, namely cytochrome c oxidase subunits 1 (CO1) and 12S ribosomal DNA (12S rDNA) were used as genetic markers. The assessment of the genetic diversity of the Echinococcus strains showed the presence of the E. granulosus sensu stricto complex and disclosed an apparent dominance of the G1 genotype within the G1-G3 complex. Furthermore, several mitochondrial variants were identified for the G1 and G2 genotypes of E. granulosus s.s. complex. Overall, the findings were of epidemiological relevance and highlighted a high potential risk of zoonotic infection.