Viral meningitis and encephalitis

Viral meningitis and encephalitis occur at all stages of life. They can represent disease at its primary site of replication (e.g. rabies) or be part of an infection syndrome (e.g. HIV). A large proportion of cases go unconfirmed by laboratory diagnosis despite use of all available laboratory techniques. They can be sporadic or epidemic, but with changing environmental and societal conditions, infective agents can emerge for the first time (e.g. Nipah, Hendra and Zika viruses) or reappear after a period of good control through vaccination (e.g. mumps virus, poliovirus). Specific antiviral treatment is currently limited. Prevention is by public health measures and vaccination.