Abstract: Objective　To investigate the population dynamics and Echinococcus infections in small rodents around human settlement in Yushu City, Qinghai Province. Methods Rodents were captured using the mouse trap method in pastures from Batang Township and Longbao Township of Yushu City, Qinghai Province on May, August and October, 2018. The body weight and snout⁃vent length of all captured rodents were measured, and the species was identified according to the rodent morphology. Genomic DNA was extracted from rodent liver specimens and lesion specimens, and the mitochondrial cox1 gene of Echinococcus was amplified using PCR assay for identification of parasite species. In addition, the tissue specimens positive for PCR assay were sampled for pathological examinations. The prevalence of Echinococcus infections was estimated in rodents, and a phylogenetic tree was created based on Echinococcus cox1 gene sequences. Results　A total of 285 small rodents were captured, including 143 Ochotona curzoniae (50.2%), 141 Lasiopodomys fuscus (49.5%), and 1 Neodon irene (0.3%), and there was a remarkable variation in habitat selection among these three rodent species. The number of L. fuscus correlated positively with vegetation coverage (r = 0.350, P = 0.264), with the greatest number seen in August, and the number of O. curzoniae negatively with vegetation coverage（r = –0.371, P = 0.235), with the highest number seen in August and the lowest number in May. The female/male ratios of O. curzoniae and voles were 1∶0.96 and 0.82∶1, respectively. The body weight (r = 0.519, P < 0.01) and snout⁃vent length (r = 0.578, P < 0.01) of O. curzoniae showed a tendency towards a rise with month, while the body weight (r = –0.401, P < 0.01) and snout⁃vent length (r = –0.570, P < 0.01) of voles presented a tendency towards a reduction with month. No Echinococcus infection was detected in voles, while 2.1% prevalence of E. shiquicus infection was seen in O. curzoniae. Phylogenetic analysis revealed consistent sequences of cox1 gene from E. shiquicus in Yushu City of Qinghai Province and Shiqu County, Ganzi Tibetan Autonomous Prefecture of Sichuan Province. Conclusions　The small rodents around the human settlement in Yushu City of Qinghai Province mainly include O. curzoniae and L. fuscus, with the greatest numbers seen in May and August, respectively. Following the concerted efforts for echinococcosis control, the prevalence of Echinococcus infections is low in small rodents around the human settlement in Yushu City; however, there is still a risk of echinococcosis transmission.

Key words: Echinococcosis, Echinococcus shiquicus, Rodent, Ochotona curzoniae, Lasiopodomys fuscus, cox1 gene, Population dynamic, Yushu City

摘要： 目的　调查青海省玉树市人群定居点周围小型啮齿类动物种群动态及其棘球蚴感染情况。方法　2018年5、8月和10月，在青海省玉树市巴塘乡和隆宝镇牧场布置鼠夹捕捉啮齿类动物，测量捕获的动物体质量和头体长并根据形态学进行种类鉴定。提取动物肝脏组织和病灶组织DNA，PCR扩增棘球绦虫线粒体cox1基因进行虫种鉴定，PCR检测阳性组织样本进行病理观察。计算啮齿类动物棘球蚴感染率，基于棘球绦虫cox1基因序列构建系统进化树。结果　累计捕获小型啮齿类动物285只，其中高原鼠兔143只（50.2%）、青海田鼠141只（49.5%）、高原松田鼠1只（0.3%），高原鼠兔和田鼠在栖息地选择上表现出明显分离。青海田鼠数量与植被覆盖度呈正相关（r = 0.350，P = 0.264），在8月达到最高水平；高原鼠兔数量与植被覆盖度呈负相关（r = –0.371，P = 0.235），在8月活动频率最低、5月活动频率最高。高原鼠兔雌雄性别比例为1∶0.96，田鼠雌雄性别比例为0.82∶1；高原鼠兔体质量（r = 0.519，P < 0.01）和头体长（r = 0.578，P < 0.01）随月份呈逐渐增大趋势，田鼠体质量（r = –0.401，P < 0.01）和头体长（r = –0.570，P < 0.01）随月份呈逐渐下降趋势；田鼠中未发现棘球绦虫感染，高原鼠兔石渠棘球绦虫感染率为2.1%。系统进化树显示，青海省玉树市石渠棘球绦虫和四川省甘孜藏族自治州石渠县境内发现的石渠棘球绦虫cox1基因序列一致。结论　青海省玉树市人群定居点周围小型啮齿类动物主要为高原鼠兔和青海田鼠，高原鼠兔和青海田鼠分别在5月和8月达到最大种群数量；随着玉树市棘球蚴病防治措施的有效实施，人群定居点周围小型啮齿类动物棘球蚴感染率处于较低水平，但仍然存在棘球蚴病传播风险。

关键词: 棘球蚴病, 石渠棘球绦虫, 啮齿类动物, 高原鼠兔, 青海田鼠, cox1基因, 种群动态, 玉树市