Zhou Jianglin, Xing Yaling, Zhou Zhe, Wang Shengqi
Beijing Institute of Microbiology and Epidemiology, Beijing, China.
Front Microbiol. 2023 Jan 12;13:967999. doi: 10.3389/fmicb.2022.967999. eCollection 2022.
The Usutu virus (USUV) is an emerging arbovirus virus maintained in the environment of Afro-Eurasia a bird-mosquito-bird enzootic cycle and sporadically infected other vertebrates. Despite primarily asymptomatic or mild symptoms, humans infected by USUV can develop severe neurological diseases such as meningoencephalitis. However, no detailed study has yet been conducted to investigate its evolution from the perspective of codon usage patterns. Codon usage choice of viruses reflects the genetic variations that enable them to reconcile their viability and fitness toward the external environment and new hosts. This study performed a comprehensive evolution and codon usage analysis of USUVs. Our reconstructed phylogenetic tree confirmed that the circulation viruses belong to eight distinct lineages, reaffirmed by principal component analysis based on codon usage patterns. We also found a relatively small codon usage bias and that natural selection, mutation pressure, dinucleotide abundance, and evolutionary processes collectively shaped the codon usage of the USUV, with natural selection predominating over the others. Additionally, a complex interaction of codon usage between the USUV and its host was observed. This process could have enabled USUV to adapt to various hosts and vectors, including humans. Therefore, the USUV may possess a potential risk of cross-species transmission and subsequent outbreaks. In this respect, further epidemiologic surveys, diversity monitoring, and pathogenetic research are warranted.
乌苏图病毒（USUV）是一种在亚非欧大陆环境中传播的新兴虫媒病毒，它在鸟类-蚊子-鸟类的动物疫源循环中存在，并偶尔感染其他脊椎动物。尽管感染USUV的人类主要表现为无症状或症状轻微，但也可能会发展为严重的神经系统疾病，如脑膜脑炎。然而，尚未有详细研究从密码子使用模式的角度对其进化进行调查。病毒的密码子使用选择反映了遗传变异，这些变异使它们能够在生存能力和对外部环境及新宿主的适应性之间取得平衡。本研究对乌苏图病毒进行了全面的进化和密码子使用分析。我们重建的系统发育树证实，流行的病毒属于八个不同的谱系，基于密码子使用模式的主成分分析再次证实了这一点。我们还发现密码子使用偏好相对较小，并且自然选择、突变压力、二核苷酸丰度和进化过程共同塑造了乌苏图病毒的密码子使用，其中自然选择占主导地位。此外，还观察到乌苏图病毒与其宿主之间密码子使用的复杂相互作用。这一过程可能使乌苏图病毒能够适应包括人类在内的各种宿主和载体。因此，乌苏图病毒可能具有跨物种传播及后续爆发的潜在风险。在这方面，有必要进一步开展流行病学调查、多样性监测和致病机制研究。
