Is an Infection Really Behind Alzheimer's? Shocking New Theory Alarms Scientists

Theory Briefing

• Porphyromonas gingivalis, the bacterium behind gum disease, was found in the brain tissue of people who died with Alzheimer's disease.
• The discovery challenges the long-dominant amyloid-plaque model by suggesting an infectious agent may drive — or worsen — neurodegeneration.
• If a common oral bacterium can reach the brain, routine dental hygiene could carry stakes far beyond cavities and tooth loss.
• The finding reopens debate over whether Alzheimer's is primarily a disease of the brain or a systemic condition with an unexpected entry point.