Molecular characterization of Echinococcus granulosus in sheep and goats of Peloponnesus, Greece

Although cystic echinococcosis (CE) has been a recognized public health problem in Greece, molecular data are lacking regarding the types and prevalences of infecting strains of the etiological agent Echinococcus granulosus. Therefore, we investigated the prevalence of CE and determined the infecting genotypes in sheep and goats in Peloponnesus, a large region of southern Greece. Liver and lung samples were obtained from 210 sheep and 190 goats slaughtered between January and December 2005, and the number, morphology, and fertility of hydatid cysts were determined. Protoscoleces or germinal layers were collected from individual cysts (20 sheep and 20 goats), and DNA was extracted. A polymerase chain reaction (PCR)/seminested PCR system was used to distinguish the G1, G5, and G6/G7 strains, and a specific molecular diagnosis was obtained by sequencing PCR-amplified mitochondrial DNA encoding cytochrome c oxidase subunit 1 and NADH dehydrogenase I genes. The prevalence of CE was 30.4% in sheep and 14.7% in goats; fertile cysts were found in 16.2 and 7.4%, respectively. Overall, 18 of 20 sheep harbored the G1 genotype (common sheep strain), while the remaining two animals had the G3 (buffalo) strain. All 20 goats were infected with the G7 (pig) strain. These results document the prevalence of E. granulosus infection in food animals in this geographical area and reveal for the first time the presence of, at least, three parasite genotypes.