An association between a common bacteria and Alzheimer's disease has been discovered by researchers at the Philadelphia College of Osteopathic Medicine.

The link was found between the bacterium clyamydia pneumoniae and the amyloid plaques found in the brains of patients with sporadic, non-hereditary Alzheimer's disease, according to report presented at the 8th International Conference on Alzheimer's disease and Related Disorders in Sweden.

Prior research has found chlamydia pneumoniae in 90 percent of the brains taken from deceased patients who had suffered from Alzheimer's disease.

The new study shows that the bacterium, when sprayed into the noses of mice, can cause progressive deposition of amyloid plaques, creating a partial model of Alzheimer's disease.

"We believe this could be a trigger mechanism for the pathology of Alzheimer's disease," said Brian Balin, lead researcher. "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. We also believe that our isolation of chlamydia pneumoniae from the human Alzheimer's diseased brain and induction of pathology in normal mice is proof of principle that this can be a causative mechanism turning on pathology."

Most of the world's population has been exposed to the chlamydia pneumoniae by age 70. It primarily causes inflammatory lung disease, but also can infiltrate the brain.

Other sources: Philadelphia College of Osteopathic Medicine