Genetic diversity of Echinococcus granulosus sensu stricto infecting humans in western Algeria

Human cystic echinococcosis is a zoonosis due to the flat worm Echinococcus granulosus sensu lato. The disease remains a major public health problem in Northern Africa. Molecular typing enables a better understanding of the parasite circulation from animals to humans. In this study, we investigated the genotypic diversity of 46 Echinococcus granulosus isolates collected from humans in the western part of Algeria by the mean of partial sequences of 4 mitochondrial loci, namely cox1a, cox1b, nd3, and atp6. Nucleotide polymorphism ranges from 0.6 (nd3) to 2.7% (cox1a). Eight alleles had not been previously reported. Multilocus analysis showed that all the isolates were from the Echinococcus granulosus sensu stricto (G1 genotype). Nineteen different haplotypes made of the concatenation of 4 sequenced loci were observed, the most common type clustering 13 isolates (36.1%). Twelve of these haplotypes had never been described previously and fifteen (41.7%) haplotypes were represented by only one isolate. Using sequences from this study and others retrieved from the GenBank database, any clustering either according to the geographic origin within Algeria or according to the human or animal origin of the isolates could be demonstrated supporting that genotype G1 population genetics has been shaped by intensive animal breeding.