Alphaviruses such as chikungunya and western equine encephalitis viruses are important human pathogens transmitted by mosquitoes that have recently caused large epidemic and epizootic outbreaks. The epidemic potential of alphaviruses is often related to enhanced mosquito transmission. Tissue barriers and antiviral responses impose bottlenecks to viral populations in mosquitoes. Substitutions in the envelope proteins and the presence of repeated sequence elements (RSEs) in the 3’UTR of epidemic viruses were proposed to be specifically associated to efficient replication in mosquito vectors. Here, we discuss the molecular mechanisms that originated RSEs, the evolutionary forces that shape the 3’UTR of alphaviruses, and the significance of RSEs for mosquito transmission. Finally, the presence of RSEs in the 3’UTR of viral genomes appears as evolutionary trait associated to mosquito adaptation and emerges as a common feature among viruses from the alphavirus and flavivirus genera.

基孔肯雅病毒和西部马脑炎病毒等甲病毒是由蚊子传播的重要人类病原体，最近引起了大规模的流行病和动物流行病暴发。甲病毒的流行潜力通常与蚊子传播增强有关。组织屏障和抗病毒反应对蚊子的病毒种群构成了瓶颈。包膜蛋白的替换和流行病毒 3'UTR 中重复序列元素 (RSE) 的存在被认为与蚊子载体中的有效复制特别相关。在这里，我们讨论了产生 RSE 的分子机制、形成甲病毒 3'UTR 的进化力量，以及 RSE 对蚊子传播的重要性。最后，