Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan.
Research Center for Biosafety, Laboratory Animal, and Pathogen Bank, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan.
Sci Rep. 2024 Sep 18;14(1):21815. doi: 10.1038/s41598-024-71791-8.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been detected or isolated from domestic cats. It is unclear whether cats play an important role in the SARS-CoV-2 transmission cycle. In this study, we examined the susceptibility of cats to SARS-CoV-2, including wild type and variants, by animal experiments. Cats inoculated with wild type, gamma, and delta variants secreted a large amount of SARS-CoV-2 for 1 week after the inoculation from nasal, oropharyngeal, and rectal routes. Only 100 TCID of virus could infect cats and replicate well without severe clinical symptoms. In addition, one cat inoculated with wild type showed persistent virus secretion in feces for over 28 days post-inoculation (dpi). The titer of virus-neutralizing (VN) antibodies against SARS-CoV-2 increased from 11 dpi, reaching a peak at 14 dpi. However, the omicron variant could not replicate well in cat tissues and induced a lower titer of VN antibodies. It is concluded that cats were highly susceptible to SARS-CoV-2 infection, but not to the Omicron Variant, which caused the attenuated pathogenicity.
严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）已在国内猫群中被检测或分离到。目前尚不清楚猫在 SARS-CoV-2 的传播循环中是否扮演着重要角色。在本研究中，我们通过动物实验来检测猫对 SARS-CoV-2（包括野生型和变异株）的易感性。接种野生型、伽马和德尔塔变异株的猫，在接种后第 1 周，经鼻、口咽和直肠途径可大量排出 SARS-CoV-2。仅需 100 个组织培养感染剂量（TCID）的病毒即可感染猫，并在无严重临床症状的情况下很好地复制。此外，一只接种野生型的猫在接种后 28 天以上持续从粪便中排出病毒。针对 SARS-CoV-2 的病毒中和（VN）抗体滴度从 11 天开始增加，在 14 天达到峰值。然而，奥密克戎变异株在猫组织中不能很好地复制，诱导的 VN 抗体滴度较低。综上可知，猫对 SARS-CoV-2 感染高度易感，但对奥密克戎变异株不易感，后者导致了致病性减弱。
