近日，中国农业科学院研究生院2017级尼日利亚籍博士生John Ohiolei在兰州兽医研究所贾万忠研究员的指导下，在中科院JCR医学大类2区Top期刊《寄生虫和载体》(Parasties & Vectors, IF=3.031)上在线发表了一篇题为“中国西藏自治区牦牛和绵羊棘球蚴（Echinococcus spp. larvae）线粒体DNA遗传变异的研究”的研究性论文。本研究调查了中国西藏自治区四个县细粒棘球绦虫广义种（Echinococcus granulosus sensu lato）的物种多样性和遗传变异特点。首次在西藏自治区牦牛中发现存在加拿大棘球绦虫（E. canadensis）G6基因型，并强调在棘球蚴病防控中应该考虑到该虫种（基因型）感染人畜的潜在风险，有必要对牦牛和其他潜在中间宿主进行全面的调查和分析。

Recently, a GSCAAS PhD student John Ohiolei under the supervision of Professor Wan-Zhong Jia at Lanzhou Veterinary Research Institute, CAAS published an on-line research article entitled “Genetic variation of Echinococcus spp. in yaks and sheep in the Tibet Autonomous Region of China based on mitochondrial DNA” in Parasites & Vectors(CAS-Q2 Top journal, IF=3.031). In this study, they investigated the species diversity and genetic variation of Echinococcus granulosus sensu lato in four counties in the Tibet Autonomous Region (TAR) of the People’s Republic of China. The study demonstrates the first detection of the G6 genotype of E. canadensis in a yak in the Tibet Autonomous Region and emphasizes the need for ongoing control efforts to comprehensively investigate yaks and other potential intermediate hosts for the prevalence of this genotype in the region considering its zoonotic potential.

囊性棘球蚴病（CE）是由细粒棘球绦虫广义种（E. granulosus s.l.）的幼虫——棘球蚴寄生于人和动物的肝、肺等器官所引起的一种重要人畜共患病。在细粒棘球绦虫复合群（E. granulosus complex）中，通过对棘球绦虫线粒体DNA的研究，人们认识到线粒体DNA高度遗传变异性影响着棘球绦虫虫种（基因型）的感染性和对中间宿主嗜性。研究结果表明，到目前为止，这个复合群由细粒棘球绦虫狭义种（Echinococcus granulosus sensu stricto）（G1/G3）、马棘球绦虫（E. equinus ）（G4）、奥氏棘球绦虫（E. ortleppi）（G5）、加拿大棘球绦虫（E. canadensis）（G6、G7、G8和G10）和狮棘球绦虫（E. felidis）组成。中国尤其是青藏高原地区是囊型棘球蚴病最严重的公共卫生问题，中国囊型棘球蚴病的经济损失和负担约占全球的90%。

Cystic echinococcosis (CE) is a parasitic zoonosis caused by tapeworm species of Echinococcus granulosus (s.l.), which infect humans and livestock leading to the formation of hydatid cyst by the metacestode larval stages mainly in the liver and lungs. Within the E. granulosus complex, high genetic variation which affects species/genotype infectivity and preference to intermediate hosts has been recognised based on studies of parasite mitochondrial DNA. So far, known species in this complex include E. granulosus (sensu stricto) (G1/G3), E. equinus (G4), E. ortleppi (G5), E. canadensis (G6, G7, G8 and G10) and E. felidis. CE constitutes a serious public health concern in China (especially in the Qinghai-Tibet Plateau) where it accounts for about 90% of global CE burden.

本研究对采自西藏自治区绵羊和牦牛的85个棘球蚴包囊进行了线粒体DNA变异的分析，以确定该地区细粒棘球绦虫广义种的遗传多样性和变异。

In this study, the mitochondrial DNA of 85 hydatid cysts collected overtime from sheep and yaks in TAR were investigated to determine the species diversity and genetic variation of E. granulosus (s.l.) in the region.

研究表明，在采集的85个绵羊（54个）和牦牛（31个）包囊标本中，有83个为细粒棘球绦虫狭义种（E. granulosus s.s.），其中G1为77个，G3为6个，其余2个为加拿大棘球绦虫（E. canadensis）（G6）。低成对固定指数（FST）表明绵羊和牦牛分离株之间没有遗传差异性。同时，以前的调查已经发现中国不同地区的绵羊、山羊、牦牛和/或人类中存在少量加拿大棘球绦虫（E. canadensis）（G6、G7、G8和G10）感染，而G6基因型以前在西藏自治区的绵羊调查中也有报道。本研究首次在牦牛中发现了G6基因型的寄生。根据本研究的结果，我们建议今后的调查和控制工作中，应考虑全面调查这些基因型对其他潜在中间宿主的感染率和遗传多样性，并将其纳入现有的囊型棘球蚴病控制计划中。

Out of 85 hydatid cyst samples collected from slaughtered sheep (n = 54) and yaks (n = 31), the results identified 83 as E. granulosus (s.s.) G1 (n = 77), G3 (n = 6) while 2 were identified as E. canadensis G6. A low FST indicated no genetic difference between isolates from sheep and yaks. Meanwhile, previous investigations have identified pockets of infection with E. canadensis (G6, G7, G8 and G10) in sheep, goats, yaks and/or humans in different parts of China while the G6 genotype has been previously reported in sheep in the Tibet Autonomous Region. The detection of the G6 genotype in a yak in the present study represents the first in TAR. Based on the result of this study, we recommended future surveys and control efforts to comprehensively investigate other potential intermediate hosts for the prevalence and genetic diversity of the E. canadensis group (G6, G7, G8 and G10) across the country and their inclusion into the existing 

CE control program.

Median-joining networks of Tibetan population of 83 Echinococcus granulosus (s.s.) isolates (yak, n = 30, sheep, n = 53) (a) nad1 (894 bp) and (b) nad5 (680 bp). Circle sizes are proportional to the corresponding haplotype frequencies. Hatch marks represent the number of mutations.