Echinococcus granulosus sensu stricto hydatid cysts in human and livestock from northeastern Algeria: Molecular characterization based on nad5 and cox1 and fertility assessment

Cystic Echinococcosis (CE) is a major helminthic zoonosis caused by the larval stage of Echinococcus granulosus, particularly highly endemic in several Mediterranean regions, including Algeria. Humans are accidental hosts, while animals such as livestock act as intermediate hosts. This study aimed to update the fragmented epidemiological picture of CE in Algeria, by combining the knowledge on cysts fertility, and protoscolex viability with molecular strains assignment. In particular, the genetic typing of Echinococcus granulosus from humans (n = 16), cattle (n = 15), sheep (n = 15), and goat (n = 1) collected in the northeastern Setif region, were performed using two partial mitochondrial markers used for a precise strains and variant call, the classic partial cox1 and the recently developed nad5, used in this area for the first time. Results revealed a predominance of E. granulosus sensu stricto strain G1, with haplotype variants circulating in both humans and animals. Interestingly, G3 strain was reported only in a human patient, while G3 haplotype variants in both humans and animals. Fertility rate was lower but not negligible in cattle (18.2%), and high in sheep and humans (80.9% and 95.6%, respectively), and the viable cysts showed different anatomical distributions across species: in cattle, 43% were pulmonary and 57% hepatic; in sheep, 74.5% were located in the lungs and 25.5% in the liver. Such data highlights the crucial role of livestock in maintaining E. granulosus transmission in the area.