Encephalitis is an acute inflammation of the brain. Encephalitis with meningitis is known as meningoencephalitis. Symptoms include headache, fever, confusion, drowsiness, and fatigue. More advanced and serious symptoms include seizures or convulsions, tremors, hallucinations, and memory problems. Viral encephalitis can occur either as a direct effect of an acute infection, or as one of the sequelae of a latent infection. The most common causes of acute viral encephalitis are rabies virus, Herpes simplex, poliovirus, measles virus, and JC virus. Other causes include infection by flaviviruses such as Japanese encephalitis virus, St. Louis encephalitis virus or West Nile virus, or by Togaviridae such as Eastern equine encephalitis virus (EEE virus), Western equine encephalitis virus (WEE virus) or Venezuelan equine encephalitis virus (VEE virus). Henipaviruses; Hendra (HeV) and Nipah (NiV), are also known to cause viral encephalitis.
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