Role of infection in the pathogenesis of Alzheimer's disease: implications for treatment.

While our understanding of the neuropathology of Alzheimer's disease continues to grow, its pathogenesis remains a subject of intense debate. Genetic mutations contribute to a minority of early-onset autosomal dominant cases, but most cases are of either late-onset familial or sporadic form. CNS infections, most notably herpes simplex virus type 1, Chlamydophila pneumoniae and several types of spirochetes, have been previously suggested as possible aetiological agents in the development of sporadic Alzheimer's disease but with little consistent evidence.