There’s been a major breakthrough in the understanding of Alzheimer’s disease. Every face-to-face friend I’ve told about this has found it fascinating, and one of my regulars has rightly suggested I should blog it. It seems many cases of Alzheimer’s may be due to brain infection by the herpes simplex Type I virus — the one that gives you cold sores. Researchers at the University of Manchester have found herpes-simplex DNA in the abnormal beta-amyloid plaques found in the brains of Alzheimer’s patients. The implications are huge.
First, this means that the etiology of Alzheimer’s is probably pretty simple. Herpes simplex type I is dirt-common — most people have asymptomatic infection by it in their peripheral nervous systems. When you get old and your immune system loses some oomph, the virus can cross the blood-brain barrier and start doing damage. The plaques seem to be the result of virus-induced cell death.
Second, this suggests a treatment strategy for people with Alzheimer’s-like symptoms — dose ’em with antivirals. This might slow or stop the disease progression.
This result continues a trend. In recent years, several chronic diseases once thought to be much more complex and obscure have turned out to very likely be slow infections. Ulcers, congestive heart failure, and arthritis are among them. Control of infectious pathogens has been receding from the medical limelight since the victories over polio and tuberculosis in my childhood; for this, and other reasons (including the disturbing increase in antibiotic-resistent bacteria) it may now be poised for a comeback.