Reviewing these cascades, like ROS/oxidative stress related to dopamine, iron, nitric oxide, loss of glutathione, mitochondrial dysfunction, excitotoxicity, cytotoxic cytokines, microglial M1/M2 activities, JAK-STAT pathway, the role of Toll-receptors, NFκB we aim to elucidate the viral impact leading to accumulation/aggregation of proteins characteristic for PD and AD, α-synuclein (PD), and ß-amyloid respective Tau-protein (AD). The gene discussed is SOAT1; the disease is Alzheimer disease.