Study of genetic diversity of Echinococcus granulosus sensu stricto in France based on full cox1 gene

Cystic echinococcosis (CE) is a worldwide zoonosis caused by Echinococcus granulosus sensu lato (s.l.) complex with E. granulosus sensu stricto (s.s.) the main species responsible of humans CE. This study highlights the genetic diversity of E. granulosus s.s. in France to clarify the parasite's circulation in livestock, interactions with wildlife, and distinguish autochthonous from imported cases of human CE. A total of 129 full cox1 gene sequences were obtained: 101 from livestock, 12 from wildlife, and 16 from human CE patients operated in France. This study reveals a broad genetic diversity of E. granulosus s.s. in France and little differentiation between sheep and cattle parasite populations, or between geographic areas. The G3 genotype (67 %) was predominant, mainly in sheep from the Alps, a historical focus in Southeast France. Despite farms being less than 20 km apart, no common haplotype was found, suggesting separate infections sources, without excluding the potential role of transhumance in parasite transmission. Haplotypes shared by livestock and wolves remain insignificant in maintaining the life cycle given the low occurrence of infection in wolves. Concerning the 16 cases of human CE, full cox1 haplotypes provide additional genetic argument supporting their status as mainly imported cases. Nevertheless, as autochthonous human cases have already been reported, further genetic characterization of E. granulosus s.s. in both humans and livestock in France is important to identify epidemiologic links and develop action plans to prevent and control this parasite.