Chronic viral infections can lead to mental deterioration

Chronic viral infections like CMV, HSV-2 or toxoplasma can contribute to subtle mental deterioration in apparently healthy older adults, a study has revealed. Many cross-sectional studies, which capture information from a single time point, have suggested a link between exposure to cytomegalovirus (CMV) and herpes simplex viruses (HSV) 1 and 2, as well as the protozoa Toxoplasma gondii with decreased cognitive functioning, said lead investigator Vishwajit Nimgaonkar from the University of Pittsburgh School of Medicine in the US.

"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," he said.
For the study, published in the journal Alzheimer's Disease and Associated Disorders, researchers looked for signs of viral exposures in blood samples collected of more than 1,000 participants of 65 years and older.

They were evaluated annually for five years to investigate cognitive change over time. CMV, HSV-2 or toxoplasma exposure is associated with different aspects of cognitive decline in older people that could help explain what is often considered to be age-related decline, the study found. "It's possible that these viruses, which can linger in the body long after acute infection, are triggering some neurotoxic effects," Nimgaonkar added.