Washington - A novel study by researchers from the Mayo Clinic in Minnesota has found that a certain group of viruses known to trigger a variety of sickness, right from common cold to polio could also hamper cognitive abilities later in life. This infamous virus called picornavirus and its ilk can cause memory loss with a cumulative effect, spread over a lifetime, which can show up as an apparent shortfall in cognitive abilities.
Charles Howe, lead author of the study said, "We think picornavirus family members cross into the brain and cause a variety of brain injuries. For example, the polio virus can cause paralysis. 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."
To examine the effects of picornaviruses on potential memory loss, researchers injected mice with a virus, a counterpart of the human poliovirus called Theiler's murine encephalomyelitis virus. The study found that the infected mice were struggling to navigate a maze, with some of them completely disabled while others still managed to sail through.
When their brains were studied, it became evident that the virus infection had also wrecked damage in the hippocampus region, which is associated with learning and memory.
The researchers wrote in their report "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 impairment as the individual ages. We hypothesize that mild memory and cognitive impairments of unknown etiology may, in fact, be due to accumulative loss of hippocampus function caused by repeated infection with common and widespread neurovirulent picornaviruses."
The findings of the study are published in the journal Neurobiology of Disease.