Are infections seeding some cases of Alzheimer’s disease?

A fringe theory links microbes in the brain with the onset of dementia. Now, researchers are taking it seriously.

Some scientists think that microbes such as the herpes simplex virus 1 (shown here on an epithelial cell) could trigger some cases of Alzheimer’s disease. Credit: SPL

Two years ago, immunologist and medical-publishing entrepreneur Leslie Norins offered to award US$1 million of his own money to any scientist who could prove that Alzheimer’s disease was caused by a germ.

The theory that an infection might cause this form of dementia has been rumbling for decades on the fringes of neuroscience research. The majority of Alzheimer’s researchers, backed by a huge volume of evidence, think instead that the key culprits are sticky molecules in the brain called amyloids, which clump into plaques and cause inflammation, killing neurons. (See link for article)



Important quote:

Several microbes have been proposed as triggers of Alzheimer’s, including three human herpes viruses and three bacteria: Chlamydia pneumoniae, a cause of lung infections; Borrelia burgdorferi, the agent of Lyme disease; and, most recently, Porphyromonas gingivalis, which leads to gum disease. In theory, any infectious agent that can invade the brain could have this trigger role (there’s no good evidence, however, that SARS-CoV-2, the virus behind COVID-19, has this ability).

It’s also sad that Alzheimer’s research has been pigeon-holed for so long:,

This article contains Norrins’ paper in the comment section. The article above states there are 40 studies in the cue vying for the 1 million cash prize in March, when the challenge results will be announced: