The West Nile virus (WNV), isolated in 1937, is an arbovirus (arthropod-borne virus) that infects thousands of people each year. Despite its burden on global health, little is known about the virus’ biological and evolutionary dynamics. As several lineages are endemic in West Africa, we obtained the complete polyprotein sequence from three isolates from the early 1990s, each representing a different lineage. We then investigated differences in growth behavior and pathogenicity for four distinct West African lineages in arthropod (Ap61) and primate (Vero) cell lines, and in mice. We found that genetic differences, as well as viral-host interactions, could play a role in the biological properties in different WNV isolates in vitro, such as: (i) genome replication, (ii) protein translation, (iii) particle release, and (iv) virulence. Our findings demonstrate the endemic diversity of West African WNV strains and support future investigations into (i) the nature of WNV emergence, (ii) neurological tropism, and (iii) host adaptation.

西尼罗河病毒（WNV）于1937年分离，是一种虫媒病毒（节肢动物传播的病毒），每年感染成千上万的人。尽管它给全球健康带来负担，但对该病毒的生物学和进化动力学知之甚少。由于在西非有几个血统流行，我们从1990年代初的三个分离物中获得了完整的多蛋白序列，每个分离物代表一个不同的血统。然后，我们研究了节肢动物（Ap61）和灵长类动物（Vero）细胞系以及小鼠中四个不同的西非血统的生长行为和致病性的差异。我们发现遗传差异以及病毒-宿主相互作用可能在体外不同WNV分离株的生物学特性中发挥作用，例如：（i）基因组复制，（ii）蛋白质翻译，（iii）颗粒释放和（iv）毒力。我们的发现证明了西非WNV毒株的地方性多样性，并支持对（i）WNV出现的性质，（ii）神经向性和（iii）宿主适应性的未来研究。