Reovirus and the pathogenesis of some forms of chronic mental illness

Focal microdegenerative changes in the nuclei of the ansa peduncularis and the septum pellucidum are present in most cases of presenile and senile dementia, Parkinson's disease and schizophrenia (7,8). These nuclei interconnect and have extensive synaptic connections with the areas of the brain recently shown to contain non-cytopathic reovirus antigen and reovirus-like particles in the normal adult (9,10). The reovirus-involved regions closely approximate the overall pattern of the topography of brain atrophy in Alzheimer's dementia and Parkinson's disease. Mechanisms are suggested whereby mutant defective reovirus present in all adult human brains is responsible or related to the major forms of chronic mental illness including the common types of dementia and schizophrenia.