MT-ND1 and cholesteryl ester measurement: The aims of the present study were to molecularly identify and genotype hydatid cysts of CE patients residing in Heilongjiang Province by sequencing and analyzing mitochondrial cytochrome c oxidase subunit I (cox1), cytochrome b (cytb) and NADH dehydrogenase subunit 1 (nad1) genes, to speculate on possible transmission patterns of this cestode by homology analysis, and to understand the phylogeny of genotypes of E. granulosus s.l. by constructing neighbor-joining trees at three loci above.