Laboratory of Clinical Virology, WHO Reference Laboratory for Poliomyelitis and Measles in the Eastern Mediterranean Region, Pasteur Institute of Tunis, University Tunis El Manar (UTM), Tunis 1002, Tunisia.
Reasearch Laboratory "Virus, Vectors and Hosts: One Health Approach and Technological Innovation for a Better Health", LR20IPT02, Pasteur Institute, Tunis 1002, Tunisia.
Viruses. 2022 May 9;14(5):1007. doi: 10.3390/v14051007.
SARS-CoV-2 is constantly evolving with lineages emerging and others eclipsing. Some lineages have an important epidemiological impact and are known as variants of interest (VOIs), variants under monitoring (VUMs) or variants of concern (VOCs). Lineage A.27 was first defined as a VUM since it holds mutations of concern. Here, we report additional lineage A.27 data and sequences from five African countries and describe the molecular characteristics, and the genetic history of this lineage worldwide. Based on the new sequences investigated, the most recent ancestor (tMRCA) of lineage A.27 was estimated to be from April 2020 from Niger. It then spread to Europe and other parts of the world with a peak observed between February and April 2021. The detection rate of A.27 then decreased with only a few cases reported during summer 2021. The phylogenetic analysis revealed many sub-lineages. Among them, one was defined by the substitution Q677H in the spike (S) gene, one was defined by the substitution D358N in the nucleoprotein (N) gene and one was defined by the substitution A2143V in the ORF1b gene. This work highlights the importance of molecular characterization and the timely submission of sequences to correctly describe the circulation of particular strains in order to be proactive in monitoring the pandemic.
SARS-CoV-2 不断进化，出现新的谱系，旧的谱系则逐渐消失。有些谱系具有重要的流行病学影响，被称为关注变体（VOI）、监测变体（VUM）或关注变体（VOC）。谱系 A.27 最初被定义为 VUM，因为它具有令人担忧的突变。在这里，我们报告了来自五个非洲国家的更多关于谱系 A.27 的数据和序列，并描述了该谱系在全球的分子特征和遗传历史。根据新调查的序列，谱系 A.27 的最近共同祖先（tMRCA）估计来自 2020 年 4 月的尼日尔。随后，它传播到欧洲和世界其他地区，2021 年 2 月至 4 月达到高峰。随后，A.27 的检测率下降，2021 年夏季仅报告了少数病例。系统发育分析显示出许多亚谱系。其中，一个谱系由刺突（S）基因中的 Q677H 取代定义，一个谱系由核蛋白（N）基因中的 D358N 取代定义，一个谱系由 ORF1b 基因中的 A2143V 取代定义。这项工作强调了分子特征描述和及时提交序列的重要性，以便正确描述特定菌株的传播情况，从而能够主动监测大流行。
