MASSIMO: When researchers deliberately infected mice with this oral bacterium, the animals rapidly developed key Alzheimer’s pathology, including the buildup of amyloid-beta plaques.

Alzheimer’s may be linked to gum bacteria, new research shows.

Scientists have repeatedly found Porphyromonas gingivalis—the chief bacterium that causes periodontitis—inside the brains of people who died with Alzheimer’s.

When researchers deliberately infected mice with this… pic.twitter.com/adrZ0Q6hLX

— Massimo (@Rainmaker1973) February 7, 2026

Alzheimer’s may be linked to gum bacteria, new research shows. Scientists have repeatedly found Porphyromonas gingivalis—the chief bacterium that causes periodontitis—inside the brains of people who died with Alzheimer’s. When researchers deliberately infected mice with this oral bacterium, the animals rapidly developed key Alzheimer’s pathology, including the buildup of amyloid-beta plaques. Perhaps most alarming, the bacteria’s toxic enzymes have been detected in the brains of people showing early Alzheimer’s changes years before memory loss or other symptoms appear, suggesting the infection may quietly initiate damage long in advance. These discoveries have sparked serious interest in new treatment approaches. An experimental drug called COR388 (from the company Cortexyme) has already succeeded in lowering both bacterial load and amyloid-beta levels in preclinical models. Although large human trials are still needed, the evidence is mounting that at least some cases of Alzheimer’s may have an infectious trigger rather than being purely degenerative. [Dominy, S. S., et al. "Porphyromonas gingivalis in Alzheimer’s disease brains: Evidence for disease causation and treatment with small-molecule inhibitors", Science Advances, 5(1), eaau3333]