<prompt> The most common cause of sporadic viral encephalitis is :Japanese B encephalitisHerpes simplex encephalitisHIV encephalitisRubeola encephalitis  <response>: 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:AlphavirusesToga virusesBunyaviruses 