Paiero Adrianna, Newhouse Emily, Chan Elaine, Clair Veronic, Russell Shannon, Zlonsnik James, Prystajecky Natalie, Fraser Erin
Fraser Health Authority, Surrey, BC.
University of British Columbia, Vancouver, BC.
Can Commun Dis Rep. 2022 Jun 9;48(6):274-281. doi: 10.14745/ccdr.v48i06a05.
Since April 2020, mink have been recognized as a potential reservoir for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and a potential source of new variants. The objective of this report is to describe the epidemiological investigation and public health response to two coronavirus disease 2019 (COVID-19) outbreaks that involved both humans and farmed mink.
An outbreak was declared on December 4, 2020, following detection of two COVID-19-positive farmworkers and elevated mink mortality on a mink farm (Farm 1) in British Columbia. The second cluster was detected on Farm 3 following detection of 1) a COVID-19 case among farm staff on April 2, 2021, 2) an indeterminate result from farm staff on May 11, 2021, and 3) subsequent SARS-CoV-2-positive mink in May 2021. Quarantine of infected farms, isolation of workers and their close contacts, and introduction of enhanced infection control practises were implemented to break chains of transmission.
Among mink farmworkers, 11 cases were identified at Farm 1 and 6 cases were identified at Farm 3. On both Farm 1 and Farm 3, characteristic COVID-19 symptoms were present in farm employees before signs were observed in the minks. The viral sequences from mink and human samples demonstrated close genetic relation. Phylogenetic analyses identified mink intermediates linking human cases, suggesting anthropo-zoonotic transmission.
These were the first COVID-19 outbreaks that included infected mink herds in Canada and identified potential anthropogenic and zoonotic transmission of SARS-CoV-2. We provide insight into the positive impact of regulatory control measures and surveillance to reduce the spillover of SARS-CoV-2 mink variants into the general population.
自2020年4月以来，水貂被认为是严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的潜在宿主以及新变种的潜在来源。本报告的目的是描述针对两起涉及人类和养殖水貂的2019冠状病毒病（COVID-19）疫情的流行病学调查及公共卫生应对措施。
2020年12月4日，在不列颠哥伦比亚省的一个水貂养殖场（农场1）检测到两名COVID-19呈阳性的农场工人且水貂死亡率升高后，宣布发生疫情。在农场3检测到第二起聚集性感染，这是在2021年4月2日农场工作人员中出现1例COVID-19病例、2021年5月11日农场工作人员检测结果不确定以及随后在2021年5月检测出水貂SARS-CoV-2呈阳性之后。对受感染农场进行检疫，隔离工人及其密切接触者，并实施强化感染控制措施以阻断传播链。
在水貂养殖场工人中，农场1发现11例病例，农场3发现6例病例。在农场1和农场3，农场员工出现典型的COVID-19症状后才在水貂身上观察到症状。水貂和人类样本的病毒序列显示出密切的遗传关系。系统发育分析确定水貂是连接人类病例的中间宿主，表明存在人兽共患病传播。
这是加拿大首次出现包括感染水貂群的COVID-19疫情，并确定了SARS-CoV-2潜在的人为和人畜共患病传播。我们深入了解了监管控制措施和监测对减少SARS-CoV-2水貂变种传播到普通人群中的积极影响。
