HSV-1 and CNS: the long term effects of a lasting affair

Starting from the pioneering studies showing evidence of herpes simplex virus type-1 (HSV-1) genome in Alzheimer’s disease (AD) brains, different epidemiological and experimental reports have proposed a possible connection between AD risk and HSV-1 recurrent infections. The main hypothesis is that, beyond massive HSV-1 entry in the brain, resulting in rare, but severe form of herpetic encephalitis, milder cerebral infection may also occur, followed by latency and virus reactivations, whose damages, may accumulate over life and result in pathologic outcomes in the elderly. This paper provides a review of literature supporting HSV-1 as a risk factor for neurodegeneration and showing the possible mechanisms involved