This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
A 29-year-old patient presents with focal seizures. MRI shows frontal and temporal enhancement. What is the most probable diagnosis? 
Select and explain. 
A. Meningococcal meningitis, B. Herpes simplex encephalitis, C. Japanese encephalitis, D. Enterovirus encephalitis
B: Herpes simplex encephalitis
Answer: B: Herpes simplex encephalitis 
Explanation: In children and young adults, primary HSV infection can lead to encephalitis, by the neurotropic spread of the virus from periphery olfactory bulb.In other majorities of cases, there is the prior mucocutaneous HSV-1 infection which gets reactivated.The Clinical hallmark of HSV infection includes acute onset of fever, and focal neurological symptoms and signs, especially of the temporal lobe.Diagnosis :CSF protein and CSF lymphocytosis Brain biopsy is the gold standardHSV DNA detection in CSF by PCR has largely replaced biopsyTreatment: IV acyclovir