Investigation of the prevalence of Echinococcus multilocularis, and risk of infection, in wild canids in Ontario, Canada

加拿大安大略省野生犬科动物中多房棘球绦虫的流行情况和感染风险的调查

• 批准号: 499793-2016
• 负责人: Peregrine, Andrew
• 金额: $ 2.92万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=607679
• 关键词: Investigation; prevalence; Echinococcus; multilocularis; risk

Echinococcus multilocularis (the fox tapeworm) is a zoonotic parasite that has a high case fatality rate in people when untreated. In North America, adult E. multilocularis occur in the small intestine of foxes and coyotes. When mature, eggs are shed in the feces; if ingested by the intermediate host (e.g. wild rodents) an alveolar hydatid cyst develops in the liver. The life cycle is completed when the intermediate host is ingested by wild canids. Historically, there are two recognized endemic areas in North America; the Northern Tundra Zone, and the North Central Region that includes three Canadian provinces and 13 contiguous US states. Strangely, despite this broad geographic distribution, very few cases of E. multilocularis have been described in dogs, cats or people. Prior to 2012, E. multilocularis had never been diagnosed in Ontario. However, since then, six cases of alveolar echinococcosis have been reported in southern Ontario; four in dogs, two in non-human primates. Five of the animals had not travelled outside southern Ontario. Since this is a new, emerging threat to canine and human health, the objectives of this study are: (i) to determine the prevalence and geographic distribution of E. multilocularis in coyotes and foxes across southern Ontario, (ii) to identify risk factors associated with E. multilocularis infection in coyotes and foxes, and (iii) to identify high risk areas for infection in dogs and people in this region. These objectives will be accomplished through the collection of fecal samples from 386 coyote and 386 fox carcasses over 2 years. Thereafter, the samples will be analyzed in Sweden using a polymerase chain reaction assay considered the most sensitive diagnostic method for E. multilocularis in feces at the current time. Using spatial analysis techniques, the diagnostic data and information about the geographic place of origin of each carcass will be used to map the risk of infection for dogs and humans across southern Ontario. Risk factors for E. multilocularis infection in coyotes and foxes will also be determined. Such information is needed to determine public and animal health risks across this region.

多房棘球蚴（狐狸绦虫）是一种人畜共患寄生虫，如果不及时治疗，其病死率很高。在北美，成虫多房艾美耳球虫存在于狐狸和土狼的小肠中。成熟后，卵随粪便排出；如果被中间宿主（例如野生啮齿动物）摄入，肝脏中会形成肺泡包虫囊肿。当中间宿主被野生犬科动物摄入时，生命周期就完成了。从历史上看，北美有两个公认的流行区：北部苔原地区以及包括加拿大三个省和美国 13 个相邻州的中北部地区。奇怪的是，尽管地理分布广泛，但在狗、猫或人身上发现的多房艾美耳球虫病例却很少。 2012 年之前，安大略省从未诊断出多房艾美耳球虫。然而，此后，安大略省南部报告了六例肺泡包虫病病例；狗中有四个，非人类灵长类动物中有两个。其中五只动物没有离开过安大略省南部。由于这是对犬类和人类健康的新威胁，本研究的目标是：(i) 确定安大略省南部郊狼和狐狸中多房艾美耳球虫的流行率和地理分布，(ii) 确定风险因素与土狼和狐狸的多房艾美耳球虫感染有关，以及（iii）确定该地区狗和人感染的高风险区域。这些目标将通过在两年内从 386 只土狼和 386 只狐狸尸体中收集粪便样本来实现。此后，这些样本将在瑞典使用聚合酶链反应测定进行分析，该测定被认为是目前粪便中多房阿米巴最敏感的诊断方法。使用空间分析技术，有关每具尸体的地理位置的诊断数据和信息将用于绘制安大略省南部狗和人类的感染风险图。土狼和狐狸感染多房艾美耳球虫的危险因素也将被确定。需要此类信息来确定该地区的公共和动物健康风险。