How does herpes simplex virus cause encephalitis? Can it be life threatening?
Herpes simplex encephalitis Herpes simplex encephalitis (HSE) is one of the most severe viral infections of the human central nervous system. It is estimated to affect at least 1 in 500,000 individuals per year.[24] About 1 in 3 cases of HSE result from primary HSV-1 infection, predominantly occurring in individuals under the age of 18; 2 in 3 cases occur in seropositive persons, few of whom have history of recurrent orofacial herpes. Approximately 50% of individuals that develop HSE are over 50 years of age.[25] HSE is thought to be caused by the retrograde transmission of virus from a peripheral site on the face following HSV-1 reactivation, along a nerve axon, to the brain.[24] The virus lies dormant in the ganglion of the trigeminal cranial nerve, but the reason for reactivation, and its pathway to gain access to the brain, remains unclear. The olfactory nerve may also be involved in HSE.[26] For unknown reasons the virus seems to target the temporal lobes of the brain. Most indivi
