School of Life Sciences, East China Normal University, Shanghai, China.
National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China.
Parasit Vectors. 2020 Apr 21;13(1):207. doi: 10.1186/s13071-020-04082-6.
The pastoral area of the eastern Tibetan Plateau is highly endemic for human echinococcosis. Domestic dogs are the main definitive host for the transmission of both Echinococcus granulosus (sensu lato) and E. multilocularis to humans. To control the infection risks, a national-level canine echinococcosis prevention and control programme has been implemented since 2015 in Shiqu County, Ganze Tibetan Autonomous Prefecture, Sichuan, China. The objective of this study was to evaluate its effect on Echinococcus spp. prevalence in dogs.
We surveyed 69 households with 84 owned dogs, for dog fecal samples and dog keeping information in the villages of Rizha and Eduoma. A total of 105 dog fecal samples (75 from owned dogs and 30 unknown dog fecal samples) were collected between 2015-2017 to determine Echinococcus spp. prevalence using copro-PCR. Eight variables based on household surveys were included into a logistic regression model for significant risk factors to canine echinococcosis prevalence in dogs.
Between 2015-2017, the overall Echinococcus spp. copro-DNA prevalence decreased significantly in dogs from 51.2% (2015) to 20.0% (2017) in Rizha, and insignificantly from 11.5% (2016) to 4.3% (2017) in Eduoma. Echinococcus multilocularis was the most prevalent species continually copro-DNA detected during the entire study period, while E. granulosus was rare and not detected in 2017. Echinococcus shiquicus copro-DNA prevalence (a probable non-zoonotic wildlife species) was as high in dogs as that of E. multilocularis, although only detected in 2015 in Rizha. Unleashed dog feces were mainly collected in Rizha in 2015. Although 93.2% of owned dogs were leashed, and the monthly praziquantel dosing rate reached 97%, E. multilocularis infection could still be detected in 11.1% of owned dogs in 2017. Monthly deworming, leashing dogs 24 h per day, and the avoidance of dogs feeding on livestock viscera were significant measures to prevent canine echinococcosis infection in owned dogs.
Carrying out a canine echinococcosis prevention and control programme can significantly decrease Echinococcus spp. prevalence. The potential contact between leashed dogs and wild small mammals is still a risk for re-infection of owned dogs with E. multilocularis. This study shows that the long-term application of regular dog treatment with praziquantel in the vast and remote echinococcosis endemic areas of the eastern Tibetan Plateau can reduce transmission in dogs but remains a challenging intervention.
藏东牧区是人畜共患包虫病的高度流行区。家犬是细粒棘球绦虫（广义）和多房棘球绦虫传播给人类的主要终末宿主。为控制感染风险，自 2015 年以来，中国四川省甘孜藏族自治州石渠县实施了国家层面的犬棘球蚴病防治计划。本研究的目的是评估其对犬棘球蚴病流行率的影响。
我们对里扎和埃杜马村的 69 户家庭的 84 只家养犬进行了犬粪便样本和犬饲养信息调查。2015-2017 年间共采集了 105 份犬粪便样本（75 份来自家养犬，30 份来自未知犬粪便样本），采用聚合酶链反应（cop-PCR）检测棘球蚴病的流行率。将基于家庭调查的 8 个变量纳入犬棘球蚴病流行率的逻辑回归模型，以确定显著的危险因素。
2015-2017 年，里扎犬的棘球蚴病总 cop-DNA 流行率从 51.2%（2015 年）显著下降至 20.0%（2017 年），而埃杜马犬的流行率从 11.5%（2016 年）略有下降至 4.3%（2017 年）。多房棘球蚴一直是整个研究期间最常见的种，而细粒棘球蚴则很少见，2017 年未检测到。2015 年在里扎还检测到了棘球蚴病 cop-DNA 流行率（一种可能的非疫区野生动物种）与多房棘球蚴病相当高。尽管只有 2015 年在里扎检测到，但犬粪中释放的犬粪主要在 2015 年收集。尽管 93.2%的家养犬被拴住，每月的吡喹酮剂量率达到 97%，但 2017 年仍能检测到 11.1%的家养犬感染多房棘球蚴病。每月驱虫、24 小时拴住犬只、避免犬只食用家畜内脏是预防家养犬感染棘球蚴病的重要措施。
开展犬棘球蚴病防治计划可显著降低棘球蚴病的流行率。被拴住的犬只与野生小哺乳动物之间的潜在接触仍然是犬只重新感染多房棘球蚴病的风险。本研究表明，在藏东广阔偏远的包虫病流行地区长期应用常规驱虫药吡喹酮治疗犬只，可降低犬只的传播风险，但仍是一项具有挑战性的干预措施。
