Viral encephalitis

Viruses are the most frequent pathogens identified in cases of infectious encephalitis. Laboratory diagnosis of these infections typically employs polymerase chain reaction and/or serological testing, though next-generation sequencing may be incorporated into clinical practice in the coming years. Important causes of viral encephalitis include herpes simplex virus, varicella-zoster virus, West Nile virus, Japanese encephalitis virus, enterovirus 71, rabies virus, lymphocytic choriomeningitis virus, mumps virus, measles virus, Ebola virus, and henipaviruses. A few of these viruses are amenable to antiviral treatment, while others can be prevented with vaccination. Here, the epidemiology, clinical features, and diagnosis of viral encephalitis are reviewed, with specific reference to important causative organisms.