Alphaviruses: Population Genetics and Determinants of Emergence

Abstract

Alphaviruses are responsible for several medically important emerging diseases and are also significant veterinary pathogens. Due to the aerosol infectivity of some alphaviruses and their ability to cause severe, sometimes fatal neurologic diseases, they are also of biodefense importance. This review discusses the ecology, epidemiology and molecular virology of the alphaviruses, then focuses on three of the most important members of the genus: Venezuelan and eastern equine encephalitis and chikungunya viruses, with emphasis on their genetics and emergence mechanisms, and how current knowledge as well as gaps influence our ability to detect and determine the source of both natural outbreaks and potential use for bioterrorism. This article is one of a series in Antiviral Research on the genetic diversity of emerging viruses.

Highlights

► Alphaviruses are important causes of emerging diseases as well as biothreat agents.

► Venezuelan equine encephalitis causes equine-amplified epidemics and enzootic spillover.

► Eastern equine encephalitis virus is one of the most virulent viruses for people and equids.

► Chikungunya virus repeatedly emerged from Africa into epidemic urban cycles in Asia and Europe.

► Population genetic studies are needed to identify natural and intentional alphavirus emergences.