DataSheet_1_The SARS-CoV-2 B.1.351 Variant Can Transmit in Rats But Not in Mice.docx

Previous studies have shown that B.1.351 and other variants have extended the host range of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to mice. Sustained transmission is a prerequisite for viral maintenance in a population. However, no evidence of natural transmission of SARS-CoV-2 in wild mice has been documented to date. Here, we evaluated the replication and contact transmission of the B.1.351 variant in mice and rats. The B.1.351 variant could infect and replicate efficiently in the airways of mice and rats. Furthermore, the B.1.351 variant could not be transmitted in BALB/c or C57BL/6 mice but could be transmitted with moderate efficiency in rats by direct contact. Additionally, the B.1.351 variant did not transmit from inoculated Syrian hamsters to BALB/c mice. Moreover, the mouse-adapted SARS-CoV-2 strain C57MA14 did not transmit in mice. In summary, the risk of B.1.351 variant transmission in mice is extremely low, but the transmission risk in rats should not be neglected. We should pay more attention to the potential natural transmission of SARS-CoV-2 variants in rats and their possible spillback to humans.

既往研究业已表明，B.1.351及其它变异株已扩展了严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的宿主范围至小鼠。病毒在人群中的持续传播是维持其存在的先决条件。然而，截至目前，尚未有自然传播SARS-CoV-2于野生小鼠的证据。在本研究中，我们对B.1.351变异株在小鼠和大鼠中的复制及接触传播进行了评估。B.1.351变异株能够在小鼠和大鼠的气道中有效感染和复制。此外，B.1.351变异株在BALB/c或C57BL/6小鼠中无法传播，但可以通过直接接触在鼠类中具有中等效率的传播能力。此外，B.1.351变异株亦无法从接种叙利亚金丝雀鼠传播至BALB/c小鼠。此外，小鼠适应性SARS-CoV-2菌株C57MA14在鼠类中也未能传播。总之，B.1.351变异株在鼠类中的传播风险极低，但大鼠中的传播风险不容忽视。我们应更加关注SARS-CoV-2变异株在鼠类中的潜在自然传播及其可能对人类造成的影响。