Encephalitic Alphaviruses: Epidemiology, Pathogenesis and Vaccine Development

Eastern, Venezuelan, and Western equine encephalitis viruses (EEEV, VEEV, and WEEV) are encephalitic alphaviruses transmitted by mosquitoes throughout the Americas. Infection by these viruses can present in humans as a febrile illness; however, it may progress into potentially life-threatening encephalitis. Currently, no publicly licensed vaccines are available, and at-risk individuals are restricted to superseded vaccines. Here, we will review recent advances in our understanding of how these viruses spread among animal populations and cause disease, and how we can manage their diagnosis and treatment. Additionally, we have summarised the recent developments in vaccines against these viruses in both pre-clinical and clinical stages. Overall, global climate change and ecological disruption drive a need for public access to safe and effective vaccines against EEEV, VEEV, and WEEV, which novel platforms, such as mRNA and viral vectors, may be able to achieve.