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What is The most common cause of sporadic viral encephalitis is : and explain in detail?
“The most common virus causing sporadic cases of encephalitis in immunocompetant adult are HSV-1, VZV, EBV and less commonly enterovirus.”
Remember: Epidemic of encephalitis are caused by Arbovirus which include:

Alphaviruses
Toga viruses
Bunyaviruses