Alzheimer's Link to Infection Grows

Common Bacteria May Trigger or Accelerate the Disease

From the WebMD Archives

Oct. 11, 2002 -- Evidence is growing that there may be a link between a common bacterial infection and Alzheimer's disease. New research shows mice exposed to the bacteria developed Alzheimer's-like deposits in their brains.

The study found that when the bacteria were sprayed into the noses of healthy laboratory mice, it caused the growth of amyloid plaques in their brains, which are the same type of brain-clogging deposits found in people with Alzheimer's disease.

Previous research by the same group revealed that the bacterium, known as chlamydia pneumoniae or C. pneumoniae, was present in the brains of 90% of people who had died of Alzheimer's disease.

Researchers say most people are exposed to these bacteria at some point in their lives, and they usually do not cause any symptoms. But in some people, they can cause inflammatory lung disease or even potentially infiltrate the brain.

The researchers conclude that the isolation of C. pneumoniae in brains of people with Alzheimer's combined with the findings of this study serve as proof that the bacteria play a role in accelerating or even initiating the disease process.

"We believe this could be a trigger mechanism for the pathology in Alzheimer's disease," says researcher Brian Balin, PhD, of the Philadelphia College of Osteopathic Medicine, in a news release. "People have been suspecting this for decades but could not find anything. It is very difficult to pinpoint an infectious cause for a progressive, chronic disease."

Balin presented the research last month at the 8th International Conference on Alzheimer's Disease and Related Disorders in Sweden.

Researchers say the mice with C. pneumoniae-induced plaques developed a form of Alzheimer's that more closely resembled the disease than that in genetically altered mice normally used in Alzheimer's research. -->

WebMD Health News
© 2002 WebMD, Inc. All rights reserved.