Department of Emerging Infectious Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki, 852-8523, Japan.
National Research Center for the Control and Prevention of Infectious Diseases (CCPID), Nagasaki University, Nagasaki, Japan.
Sci Rep. 2021 Oct 28;11(1):21259. doi: 10.1038/s41598-021-00809-2.
Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently a serious public health concern worldwide. Notably, co-infection with other pathogens may worsen the severity of COVID-19 symptoms and increase fatality. Here, we show that co-infection with influenza A virus (IAV) causes more severe body weight loss and more severe and prolonged pneumonia in SARS-CoV-2-infected hamsters. Each virus can efficiently spread in the lungs without interference by the other. However, in immunohistochemical analyses, SARS-CoV-2 and IAV were not detected at the same sites in the respiratory organs of co-infected hamsters, suggesting that either the two viruses may have different cell tropisms in vivo or each virus may inhibit the infection and/or growth of the other within a cell or adjacent areas in the organs. Furthermore, a significant increase in IL-6 was detected in the sera of hamsters co-infected with SARS-CoV-2 and IAV at 7 and 10 days post-infection, suggesting that IL-6 may be involved in the increased severity of pneumonia. Our results strongly suggest that IAV co-infection with SARS-CoV-2 can have serious health risks and increased caution should be applied in such cases.
新型冠状病毒病（COVID-19）由严重急性呼吸综合征冠状病毒 2 型（SARS-CoV-2）引起，目前是全球严重的公共卫生关注问题。值得注意的是，与其他病原体的合并感染可能会使 COVID-19 症状加重，并增加死亡率。在这里，我们发现甲型流感病毒（IAV）的合并感染会导致感染 SARS-CoV-2 的仓鼠体重下降更严重，肺炎更严重且持续时间更长。两种病毒在肺部均可有效传播，彼此之间无干扰。然而，在免疫组织化学分析中，在合并感染仓鼠的呼吸道中并未在同一部位检测到 SARS-CoV-2 和 IAV，这表明两种病毒在体内可能具有不同的细胞嗜性，或者每种病毒可能在细胞内或相邻区域抑制另一种病毒的感染和/或生长。此外，在感染 SARS-CoV-2 和 IAV 的仓鼠血清中，在感染后 7 和 10 天检测到 IL-6 显著增加，这表明 IL-6 可能参与了肺炎的严重程度增加。我们的结果强烈表明，SARS-CoV-2 与 IAV 的合并感染可能会带来严重的健康风险，在这种情况下应更加谨慎。
