Molecular characterization of Echinococcus species causing human cystic echinococcosis in Algeria: predominance of Echinococcus granulosus sensu stricto.

Genotyping of cystic echinococcosis (CE) specimens enables the identification of predominant species and genotypes, yielding critical insights into disease epidemiology. Species identification is essential for the development of effective prevention and control strategies. In this context, we assessed the molecular diversity of E. granulosus sensu lato among surgically confirmed human CE cases recruited from Algerian referral hospitals. Hydatid cysts were collected from 31 patients undergoing surgery for pulmonary and/or hepatic CE in Algeria between 2022 and 2024. Hydatid fluid, cyst wall, and laminated-layer preparations were used for DNA extraction. End-point PCR coupled with Sanger sequencing, targeting the mitochondrial 12S-rrnS, nad5, and nad2 markers, was performed for species identification and genotyping, with real-time PCR (qPCR) performed in parallel. End-point PCR was successful in 29 cases (93.5%), while qPCR detected DNA of Echinococcus spp. in 30 cases (96.8%). The additional qPCR-positive sample showed late amplification but could not be assigned to a genotype because no sequence was obtained. Among the 29 molecularly characterized samples, E. granulosus sensu stricto genotype G1 was predominant and was identified in 27 samples (93.1%). One isolate was identified as E. granulosus sensu stricto genotype G3, and one as E. canadensis G6/G7. Genotype G1 and G3 cases were distributed in northern and central Algeria, while the G6/G7 isolate was detected in a patient from Tindouf, southern Algeria. These results demonstrate the predominance of E. granulosus sensu stricto genotype G1 among the molecularly characterized human cystic echinococcosis cases in this series.