The Toronto Star, Reuters Associated Press October 24, 2006
Washington – Forget where you left your glasses? Did those keys go missing again? A virus may be to blame.
A family of viruses that cause a range of ills from the common cold to polio may be able to infect the brain and cause steady damage, a team at the Mayo Clinic in Minnesota reported yesterday.
“Our study suggests that virus-induced memory loss could accumulate over the lifetime of an individual and eventually lead to clinical cognitive memory deficits,” said Charles Howe, who reported the findings in the journal Neurobiology of Disease.
The viruses, called picornaviruses, infect more than a billion people each year, and include the viruses that cause polio, colds, and diarrhea. People contract two or three such infections a year on average.
“We think picornavirus family members cross into the brain and cause a variety of brain injuries. For example, the polio virus can cause paralysis,” Howe said. “It can injure the spinal cord and different parts of the brain responsible for motor function. In the murine (mouse ) virus we studied, it did the same thing and also injured parts of the brain responsible for memory”.
The Mayo Clinic infected mice with a virus similar to human poliovirus. Infected mice later had a range of difficulties learning to navigate a maze.
When the mice were killed and their brains examined, a correlating amount of damage was seen in the hippocampus region, related to learning and memory.
One virus particularly likely to cause brain damage is enterovirus 71 which is common in Asia, the researchers said. “Our findings suggest that picornavirus infections throughout the lifetime of an individual may chip away at the cognitive reserve, increasing the likelihood of detectable cognitive impairments as the individual ages,” the researchers wrote in their report.
“We hypothesize that mild memory and cognitive impairments of unknown etiology may, in fact, be due to a cumulative loss of hippocampus function caused by repeated infection with common and widespread neurovirulent picornaviruses.”
In another study reported in the journal Neurology yesterday, U.S. researchers found that eating vegetables in old age could slow memory loss.
Elderly people who reported eating at least 2.8 servings of vegetables a day compared to people who ate less than one serving a day saw their rate of memory loss and other mental functions slow by 40 per cent over six years, the researchers found.
People who ate the most green leafy vegetables such as lettuce, kale, spinach and collards had the least memory loss, on average. The researchers said such vegetables may be effective because they contain healthy amounts of vitamin E, an antioxidant believed to help fight chemicals produced by the body that can damage cells.
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