Analysis of cytochrome c-oxidase (COI) gene of mitochondrial DNA from the Trichinella spp. in China.

Trichinella species are parasitic nematodes of great economical and health importance. In this study, approximately 400 bp of the mitochondrial cytochrome c-oxidase (COI) gene from six species of Trichinella parasites from China and two reference species (T3 and T5) was sequenced and compared. The results showed that parasites from Yunnan, Hubei, and Dongbei (north-eastern) of China were very similar to the reference T1 isolated from Dongbei. The T2 parasite was, however, more closely related to the T5 (T. murrelli); and a parasite from Henan was very different from the rest of the parasites. These results suggested that genetic differences among most of the geographic strains in China existed. The Henan isolate may represent a new strain or species that requires further investigation.