Neurodegeneration is a feature of many debilitating, incurable diseases that are rapidly rising in prevalence, such as Parkinson's disease. There is an urgent need to develop new and more effective therapeutic strategies to combat these devastating diseases. Models – from cell-based systems, to unicellular organisms, to complex animals – have proven to be a useful tool to help the research community shed light on the mechanisms underlying neurodegenerative diseases

Alzheimer’s disease (AD) is the most prevalent of the neurodegenerative amyloid diseases and is characterized by accumulation of amyloid-β and tau. Recent studies have indicated that AD may be a brain infection. Although AD has not been shown to be transmissible, the burning issue is whether the potential infectious causes are the misfolded amyloid proteins themselves, or an unidentified microorganism. The idea of a replicating protein (prion) evolved from research on the transmissible spongiform encephalopathies (TSE) represented by Creutzfeldt-Jakob disease in humans. Recognition of conventional bacterial or viral involvement in the pathogenesis of the neurodegenerative diseases could lead to new diagnostic and therapeutic approaches. This treatise encourages a more balanced research and funding approach to investigating the exciting possibility of the infectious nature of AD. Recognition of conventional bacterial or viral involvement in the pathogenesis of the neurodegenerative diseases could lead to new diagnostic and therapeutic approaches. This treatise encourages a more balanced research and funding approach to investigating the exciting possibility of the infectious nature of AD.