Neurotropic alphaviruses

Alphaviruses are members of the Togaviridae family of icosahedral, enveloped, single-strand, message-sense RNA viruses. The mosquito-borne alpha-viruses are important causes of encephalomyelitis in the Americas and are on the category B list of agents of biodefense concern. Eastern equine encephalitis (EEE), western equine encephalitis (WEE), and Venezuelan equine encephalitis (VEE) viruses are the neurotropic alphaviruses of greatest importance as causes of human encephalomyelitis and were initially recognized for their ability to cause disease in horses. Semliki Forest virus (SFV) and Sindbis virus (SINV) do not usually cause encephalitis in humans, but are studied frequently in mice as model systems for alphavirus encephalomyelitis.