Sequence analysis of mitochondrial cytochrome c oxidase 1 and cytochrome b genes of echinococcus multilocularis from human patients.

Echinococcus multilocularis (E. multilocularis) is the cause of alveolar echinococcosis (AE) in humans. Differences in gene sequence may exist among strains of E. multilocularis that are isolated from different patients in different areas of Xinjiang Uyghur Autonomous Region of China. Other studies have shown that genetic variation and biomolecular classification of E. multilocularis exists. A total of 47 AE samples were collected from AE patients for sequence analysis of mitochondrial cytochrome c oxidase 1 (cox1) and cytochrome b (cytb) genes using PCR. We compared the obtained sequences with the GenBank database to identify the parasite and 5 haplotypes were detected among the geographical isolates from cox1 and cytb, respectively. Nearly all of the samples originated from Northern Xinjiang. Homology comparison of gene haplotypes in GenBank showed that 3 cox1 haplotypes and one cytb haplotype had 100% homology with sequences in GenBank. Two cox1 haplotypes and 4 cytb haplotypes had no homology with previous deposits in GenBank and thus were considered as newly discovered gene haplotypes. This present study demonstrates that comparatively conservative intraspecific genetic variations of E. multilocularis exist in Xinjiang Uyghur Autonomous Region and the main epidemic haplotypes in Xinjiang are H1 (cox1) and H1 (cytb). Cox1 haplotypes H4, H5, and cytb haplotypes H2, H3, H4, and H5 are considered newly discovered gene haplotype sequences.