Animal Health Centre, British Columbia Ministry of Agriculture, Abbotsford, British Columbia, Canada.
British Columbia Centre for Disease Control, Vancouver, British Columbia, Canada.
J Vet Diagn Invest. 2023 Sep;35(5):528-534. doi: 10.1177/10406387231183685. Epub 2023 Jun 27.
Surveillance for SARS-CoV-2 in American mink () is a global priority because outbreaks on mink farms have potential consequences for animal and public health. Surveillance programs often focus on screening natural mortalities; however, significant knowledge gaps remain regarding sampling and testing approaches. Using 76 mink from 3 naturally infected farms in British Columbia, Canada, we compared the performance of 2 reverse-transcription real-time PCR (RT-rtPCR) targets (the envelope [] and RNA-dependent RNA polymerase [] genes) as well as serology. We also compared RT-rtPCR and sequencing results from nasopharyngeal, oropharyngeal, skin, and rectal swabs, as well as nasopharyngeal samples collected using swabs and interdental brushes. We found that infected mink were generally RT-rtPCR-positive on all samples; however, Ct values differed significantly among sample types (nasopharyngeal < oropharyngeal < skin < rectal). There was no difference in the results of nasopharyngeal samples collected using swabs or interdental brushes. For most mink (89.4%), qualitative (i.e., positive vs. negative) serology and RT-rtPCR results were concordant. However, mink were positive on RT-rtPCR and negative on serology and vice versa, and there was no significant correlation between Ct values on RT-rtPCR and percent inhibition on serology. Both the and targets were detectable in all sample types, albeit with a small difference in Ct values. Although SARS-CoV-2 RNA can be detected in multiple sample types, passive surveillance programs in mink should focus on multiple target RT-rtPCR testing of nasopharyngeal samples in combination with serology.
对（）中的 SARS-CoV-2 进行监测是全球重点，因为貂场暴发疫情可能对动物和公共卫生造成潜在影响。监测计划通常侧重于筛选自然死亡；然而，在采样和检测方法方面仍存在重大知识差距。我们使用来自加拿大不列颠哥伦比亚省 3 个自然感染农场的 76 只貂，比较了 2 种逆转录实时 PCR（RT-rtPCR）靶标（包膜[]和 RNA 依赖性 RNA 聚合酶[]基因）以及血清学的性能。我们还比较了鼻咽、口咽、皮肤和直肠拭子以及使用拭子和牙间刷采集的鼻咽样本的 RT-rtPCR 和测序结果。我们发现，受感染的貂在所有样本中通常都是 RT-rtPCR 阳性；然而，Ct 值在样本类型之间存在显著差异（鼻咽 < 口咽 < 皮肤 < 直肠）。使用拭子或牙间刷采集的鼻咽样本结果无差异。对于大多数貂（89.4%），定性（即阳性与阴性）血清学和 RT-rtPCR 结果是一致的。然而，貂在 RT-rtPCR 上呈阳性而在血清学上呈阴性，反之亦然，并且 RT-rtPCR 的 Ct 值与血清学的抑制百分比之间没有显著相关性。和 靶标都可在所有样本类型中检测到，尽管 Ct 值略有差异。虽然可以在多种样本类型中检测到 SARS-CoV-2 RNA，但貂的被动监测计划应侧重于对鼻咽样本进行多个目标 RT-rtPCR 检测，并结合血清学。
