目的 了解降低流浪犬密度对小型哺乳类动物棘球蚴感染情况的影响。 方法 于2016年4月—2020年6月,采取聘请专业捕犬人员或由公安部门搜捕流浪犬等办法在石渠县全县范围内全年搜捕流浪犬并进行集中管理（实施安乐死）。2015—2020年,每年1次从石渠县境内的国营牧场驾车至尼呷镇（乡）（行驶距离130.5 km）,沿公路观察两侧视野范围内的流浪犬,记录沿途流浪犬数量。按流浪犬数量（只）/行驶距离（km）计算流浪犬密度。分别于2016年7月、2020年7—8月,于石渠县俄多玛、温波、宜牛、虾扎、尼呷、蒙宜、格孟等乡（镇）捕捉小型哺乳类动物,现场剖检获取脏器带回实验室,取疑似棘球蚴病灶组织提取基因组DNA,PCR扩增细胞色素c氧化酶亚基1（cox1）,测序并在GenBank中进行BLAST比对以明确棘球绦虫虫种。根据PCR检测及测序比对结果计算小型哺乳类动物棘球蚴感染率。率的95%置信区间采用Clopper & Pearson 精确法进行计算,感染率的比较采用卡方检验或Fisher确切概率法进行分析。 结果 2016年4月—2020年6月,石渠县全县累计搜捕并集中管理流浪犬41 446只,每年集中管理流浪犬数量分别为26 570、4 377、5 656、4 100、743只。2015—2020年,石渠县的流浪犬密度分别为0.80、0.04、0.06、0.04、0.05和0.05只/km。2016年7月,共捕获小型哺乳类动物261只,其中鼠兔192只,田鼠69只。PCR检测结果显示,棘球蚴阳性14只,其中田鼠8只,鼠兔6只;田鼠多房棘球蚴感染率为11.6%（8/69,95%CI：5.1%~21.6%）;鼠兔多房棘球蚴感染率和石渠棘球蚴感染率均为1.6%（3/192,95%CI：0.3%~4.5%）。2020年7—8月,共捕获小型哺乳类动物270只,其中田鼠223只,鼠兔47只,PCR检测结果显示,田鼠多房棘球蚴感染率为0.5%（1/223,95%CI：0~2.5%）;鼠兔未检测到棘球蚴感染。2020年石渠县田鼠多房棘球蚴感染率较2016年显著下降（P < 0.01）,鼠兔多房棘球蚴感染率及石渠棘球蚴感染率均有所下降,但差异无统计学意义（P > 0.05）。 结论 在流浪犬具有重要流行病学意义的多房棘球蚴病流行区,控制流浪犬可显著降低田鼠多房棘球蚴感染率。

Objective To investigate the impact of reducing stray dog population on the prevalence of Echinococcus spp. in small mammals. Methods From April 2016 to June 2020, stray dogs were captured and euthanized by professional dog catchers or by the public service department, in Shiqu County of Ganzi Tibetan Autonomous Prefecture throughout the year. During 2015 to 2020, investigators drove along the highway from State-owned livestock farm to Niga Township (130.5 km) in Shiqu County, and recorded the number of stray dogs within the sight distance on both sides of the highway. The density of stray dogs in Shiqu County was calculated by dividing the number of stray dogs by the driving distance. Small mammals were captured in Edoma, Wenbo, Yiniu, Xiazha, Niga, Mengyi and Gemeng Townships of Shiqu County and dissected on-site in July 2016 and July-August 2020. Organs of small mammals were stored in 95% ethanol and transferred back to laboratory. Hydatid lesion-like tissues were sampled from the organs for extraction of genomic DNA for PCR to amplify cytochrome c oxidase subunit 1 (cox1). The amplified products of PCR were sequenced and then compared with the known sequences in GenBank through BLAST to determine the species of Echinococcus. The infection rate of Echinococcus in small mammals was calculated according to the sequencing and alignment results. The 95% confidence interval of the rate was calculated using the Clopper & Pearson exact method. The difference in the prevalence of Echinococcus in small mammals was analyzed by chi-square test or Fisher exact test. Results From April 2016 to June 2020, 41 446 stray dogs were captured and euthanized in Shiqu County, including 26 570, 4 377, 5 656, 4 100, and 743 in each year, respectively. The density of stray dogs in Shiqu from 2015 to 2020 was 0.80, 0.04, 0.06, 0.04, 0.05 and 0.05 per kilometer, respectively. In July 2016, a total of 261 small mammals were captured, including 192 pikas (Lagomorpha : Ochotonidae) and 69 voles (Rodentia : Cricetidae). There were 14 small mammals infected with Echinococcus, of which 8 were voles and 6 pikas. The infection rate of E. multilocularis metacestodes in voles in 2016 was 11.6% (8/69, 95% CI: 5.1%-21.6%). The infection rate of E. multilocularis metacestodes and E. shiquicus metacestodes in pikas in 2016 were both 1.6% (3/192, 95% CI: 0.3%-4.5%). From July to August of 2020, a total of 270 small mammals were captured, of which 223 were voles and 47 pikas. The infection rate of E. multilocularis metacestodes in voles in 2020 was 0.5% (1/223, 95%CI: 0-2.5%). No pikas were found to be infected with Echinococcus spp.. The prevalence of E. multilocularis metacestodes in voles in 2020 was significantly reduced compared with that in 2016 (P < 0.01). The infection rate of E. multilocularis metacestodes and E. shiquicus metacestodes in pikas in 2020 were both lower than that in 2016, but the difference was not statistically significant (P > 0.05). Conclusion In endemic areas where stray dogs play an important role in the transmission of E. multilocularis, measures to reduce the density of stray dogs can significantly lower the infection rate of E. multilocularis metacestodes in voles.