Abstract
In the present study, we have extended earlier taxonomic, biochemical and experimental investigations to characterize Echinococcus granulosus from various hosts in Iran utilizing DNA regions (designated p__cox__1 and p__nad__1) within the cytochrome c oxidase subunit 1 and NADH dehydrogenase 1 mitochondrial genes, respectively. An emphasis was placed on the characterization of E. granulosus isolates (cyst material) from humans, sheep, goats, cattle and camels, and on assessing their genetic relationships. PCR‐based SSCP analysis of p__cox__1 and p__nad__1 amplicons derived from individual isolates (n=148) of E. granulosus revealed five (pc1–pc5) and nine (pn1–pn9) electrophoretic profiles, respectively. Sequencing of p__cox__1 and p__nad__1 amplicons representing unique SSCP profiles demonstrated that each profile was linked unequivocally to a particular sequence and that single point mutations were readily detectable by SSCP. Phylogenetic analyses of p__cox__1 and/or p__nad__1 nucleotide sequence data were conducted using Bayesian inference and maximum likelihood tree‐building methods. Following the phylogenetic analyses of concatenated p__cox__1+p__nad__1 sequence data, including representatives of all presently recognized Echinococcus species__/__genotypes as well as Taenia saginata (as the outgroup), the majority of cyst isolates (142 of 148; 95.9%) from humans, ruminants (sheep, goats and cattle) and camels were assigned to the G1–G3 complex of E. granulosus (or E. granulosus sensu stricto), whereas some E. granulosus cysts (6 of 19; 31.6%) from camels were assigned to the G6–G10 complex (or E. canadensis). The present study reinforces the advantages of the mutation scanning‐sequencing‐phylogenetic approach to explore variation in multiple mitochondrial loci within and among Echinococcus populations, which provides a platform for future, detailed studies of the molecular epidemiology of E. granulosus in Iran and other countries. (Note: The sequences determined in the present study have been deposited in the GenBank database under accession numbers: FJ796203‐FJ796207 (p__cox__1) and FJ796208‐FJ796216 (p__nad__1)).