MAPT and Alzheimer disease: In neuronal and glial cell cultures, herpes simplex virus type 1 (HSV-1) – one of eight herpesviruses that routinely infects humans – induces molecular changes similar to those seen in Alzheimer’s disease (AD), e.g. β-amyloid accumulation6, generation of amyloid precursor protein fragments with neurotoxic potential7, and tau hyperphosphorylation8.