Molecular characterization of Echinococcus granulosus in south-eastern Romania: evidence of G1–G3 and G6–G10 complexes in humans

Echinococcus granulosus is the aetiological agent of cystic echinococcosis (CE), which is a public health problem in many eastern European countries, particularly in Romania, where the infection causes a high number of human and animal cases. To shed light on the transmission patterns of the parasite, we performed a genotyping analysis on 60 cyst samples obtained from patients who live in south-eastern Romania and who underwent surgery for liver or lung CE. DNA was extracted from the endocysts or the cyst fluids, and fragments of cytochrome c oxidase subunit 1 and NADH dehydrogenase subunit 1 mitochondrial genes (cox1 and nd1, respectively) were amplified by PCR and sequenced. We found that most of the samples analysed (59/60) belonged to the G1–G3 complex (E. granulosus sensu stricto), which contains the most widespread and infective strains of the parasite. We also identified the first human patient infected by a non-G1–G3 genotype of E. granulosus in this country. As the DNA sequence of this cyst sample showed maximum homology with the G6–G10 complex (Echinococcus canadensis), this is, in all likelihood, a G7 genotype, which is often found in pigs and dogs in most countries of eastern and south-eastern Europe.