How Chronic Viral Infections Affect the Brain

Chronic viral infections linked to cognitive decline in healthy older adults

/ Author:  / Reviewed by: Jennifer Gershman, PharmD, CPh

(RxWiki News) As people age, cognitive functions like memory and judgment can change. And viral infections might have something to do with that.

A new study from the University of Pittsburgh (UP) found that some chronic viral infections could increase the risk of cognitive deterioration in healthy older adults.

Lead study author Vishwajit Nimgaonkar, MD, said in a press release, "Our study is one of the few to assess viral exposure and cognitive functioning measures over a period of time in a group of older adults. It's possible that these viruses, which can linger in the body long after acute infection, are triggering some neurotoxic effects."

Dr. Nimgaonkar is a professor of psychiatry at UP's School of Medicine.

Previous studies have linked viral infections to decreased cognitive function. Cytomegalovirus (CMV) and herpes simplex viruses (HSV) 1 and 2, in particular, have been implicated, as has Toxoplasma gondii.

CMV is related to the viruses that cause chickenpox and mononucleosis (mono). Infection can be serious in babies and people with weakened immune systems. Herpes viruses cause cold sores, genital herpes and shingles. Toxoplasma gondii is a parasite that causes flu-like symptoms and can result in birth defects in some cases.

For their study, Dr. Nimgaonkar and team used data from the Monongahela-Youghiogheny Healthy Aging Team (MYHAT) study to look at more than 1,000 adults age 65 or older. Each year for five years, these patients were evaluated for cognitive changes like memory and language skills.

Patients who were exposed to CMV, HSV2 or toxoplasma were more likely to develop cognitive changes over the 5-year period. Those exposed to HSV1 showed no such changes.

Dr. Nimgaonkar and team weren't able to determine exactly why this cognitive decline occurred, but said that it might be related to toxins from the viruses.

This study was published Feb. 4 in the journal Alzheimer's Disease and Associated Disorders.

The National Institutes of Health and Stanley Medical Research Institute funded this research. Information on conflicts of interest was not available at the time of publication.

Review Date: 
February 7, 2016
Last Updated:
February 9, 2016