The Throat Virus Linked To A Slowdown In Your Brain

By Heather Ramsey on Sunday, May 17, 2015
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“If the human brain were so simple that we could understand it, we would be so simple that we couldn’t.” —Emerson M. Pugh

In A Nutshell

After your mid-twenties, your brain will begin to shrink. Some cognitive decline, such as forgetfulness, is inevitable if you live long enough. To help fight dementia, Public Health England is devising a test to determine your brain age. However, not all cognitive problems are related to dementia. ATCV-1, an algae virus found in the throats of some humans, has been linked to a slowdown in our brains, affecting the visual processing, spatial awareness, and attention spans of otherwise healthy individuals.

The Whole Bushel

After your mid-twenties, your brain will begin to shrink. Some cognitive decline, such as forgetfulness and impaired problem solving, is inevitable if you live long enough. To help fight dementia, Public Health England is devising a test to determine your brain age. Until it’s ready, a comparable quiz is available online (see link below) and in the book, The Anti-Alzheimer’s Prescription, written by neurology professor Vincent Fortanasce.

The questions assess your lifestyle—what you eat, how much you sleep, and whether you exercise. They also evaluate your current state of health. Based on your answers to these 25 yes or no questions, the test will compare your brain age to your chronological age. Dr. Jack Lewis, coauthor of Sort Your Brain Out, believes you can slow the decline of your brain in several ways. A lot of it is standard advice these days. He suggests reducing free radicals by limiting your consumption of red meat while increasing the amount of fresh fruits and vegetables you eat to at least five portions per day. Of course, he recommends getting at least a moderate amount of exercise. Finally, he suggests taking up hobbies that challenge you mentally, such as playing a musical instrument, playing chess, dancing, or reading.

However, not all cognitive problems are related to dementia. ATCV-1, an algae virus found in the throats of some humans, has been linked to a slowdown in our brains, affecting the visual processing, spatial awareness, and attention spans of otherwise healthy individuals. This type of chlorovirus can often be found in green algae in rivers, lakes, and ponds. Several years ago when examining the brain tissue of dead people, researchers discovered that ATCV-1 had made the jump to humans. But it was unclear whether the virus had entered the brain tissue before the individuals died.

Then scientists encountered the virus again, this time in the throat cultures of individuals with psychiatric illnesses. That spurred a study of 92 healthy people, 43 percent of whom showed infection with the virus. More concerning was the apparent link between this virus and a 10 percent slowdown in the visual processing of those healthy individuals infected with it. They also had moderately shorter attention spans and difficulty with spatial awareness. But scientists could only conclude that there was a link between ATCV-1 and a slowdown in brain function; they couldn’t prove that the virus caused the slowdown. It was possible that another unknown factor was involved.

“This is a striking example showing that the ‘innocuous’ microorganisms we carry can affect behavior and cognition,” said lead investigator Robert Yolken of Johns Hopkins. “Many physiological differences between person A and person B are encoded in the set of genes each inherits from parents, yet some of these differences are fueled by the various microorganisms we harbor and the way they interact with our genes.”

To further study the issue of causality, researchers infected some mice with the algae virus, then tested their brain function against healthy mice injected with green algae that didn’t carry the virus. The infected mice had problems with memory and attention span. Scientists also discovered that almost 1,300 genes in the hippocampus regions of these infected mice had changed. The hippocampus is the part of the brain that affects memory and spatial awareness.

Even so, this study doesn’t tell us with absolute certainty how humans are affected by ATCV-1. For now, the cognitive effects on humans are small enough that we don’t need to worry about them. But scientists are concerned that people who work around water or with seafood may suffer negative health effects from contamination with this virus. More studies are needed to find out.

Show Me The Proof

i100: Quiz: What’s your brain age?
The Independent: Forgetful? Distracted? Foggy? How to keep your brain young
PNAS: Algal virus found in humans, slows brain activity
Phys.org: Researchers identify algae-virus DNA in humans