<prompt> A 29-year-old person comes with focal seizures. MRI shows frontal and temporal enhancement. What is the most probable diagnosis?Meningococcal meningitisHerpes simplex encephalitisJapanese encephalitisEnterovirus encephalitis  <response>: In children and young adults primary HSV infection can led to encephalitis, by neurotropic spread of virus from periphery via olfactory bulb.In other majority of cases, there is prior mucocutaneous HSV-1 infection which gets reactivated.Clincial hallmark of HSV infection include acute onset of fever, and focal neurological symptoms and signs, especially of temporal lobe.Diagnosis :CSF protein and CSF lymphocytosis Brain biopsy is gold standardHSV DNA detection in CSF by PCR has largely replaced biopsyTreatment : IV acyclovir 