Molecular study of Echinococcus in west-central China.

YANG, Y.; MARA CECILIA ROSENZVIT; ZHANG, L.; ZHANG, J.; MCMANUS, D.

PARASITOLOGY

Cambridge University Press

Año: 2005 vol. 131 p. 547 - 555

0031-1820

West-central China is an important endemic focus of both alveolar and cysticechinococcosis where several species of intermediate host are commonly infectedwith Echinococcus granulosus and E. multilocularis . Isolates of E. granulosuswere collected from humans and other animals from different geographical areasof Qinghai, Ningxia, Gansu and Sichuan, and genotyped using the mitochondrialDNA marker ATP synthase subunit 6 gene (atp6). The sheep strain (G1 genotype) ofE. granulosus was shown to be the only genotype present in sheep, cattle, goats,yaks and humans in the study areas. However, some heterogeneity in the atp6sequence was evident in a number of the isolates with the most frequent changebeing a silent substitution (G/A) at position 360 compared with the G1 referencesequence representing isolates collected from the majority of hosts excepthumans. Two E. multilocularis isolates examined also had sequences that variedfrom each other and from the reference E. multilocularis atp6 sequence. Thegenotypic variation we report may reflect phenotypic differences with importantconsequences in terms of increased host infectivity for hosts by localEchinococcus strains, possibly impacting on the epidemiology and control ofechinococcosis. Such adaptations may also result in different sensitivity todrugs or increased virulence for hosts that will impede control efforts and evenaffect vaccination strategies against Echinococcus.