Flu may increase your Alzheimer's risk: Study

After a week of sore throat and body pain, severity of your flu may wear off. But a new study has claimed that such viral infections could have lasting and unseen effects on your brain.

Researchers have found that viruses such as influenza and herpes may leave brain cells vulnerable to degeneration later in life, and increase the risk of developing diseases such as Alzheimer’s and Parkinson’s.

That’s because the viruses can enter the brain and trigger an immune response – inflammation – which can damage brain cells, said Dr Ole Isacson, a professor of neurology at Harvard Medical School, who led the study.

“Viruses and other sources of inflammation may be initiating factors in some of the most common neurological diseases,” Dr Isacson was quoted as saying by LiveScience.

It’s unlikely one bout of the flu will cause significant damage. But over a lifetime, injuries to cells accumulate, and along with environmental stresses, this can kill cells and the development of brain diseases, Isacson said.
Variations in the number of infections we get may be the difference between a person developing Parkinson’s disease at age 65 or at age 95, he said.

The researchers said it’s possible that toning down the inflammation that occurs shortly after viral infection could reduce cell damage and the risk of subsequent brain disease.

In the research, published in the journal Science Translational Medicine, they pointed to a 2011 study of 135,000 people which had found that those who took ibuprofen (a medication that can reduce inflammation) were 30 per cent less likely to develop Parkinson’s over a six year period compared to those who did not take the medication.

One of the earliest evidence for the virus-brain disease link comes from the 1918 influenza pandemic, they said. In a more rigorous test of the link, a 2009 study showed that mice injected with the H5N1 flu virus developed infections in cells in a brain region known to be significantly impacted by Parkinson’s disease, Isacson said.