“Our study suggests that virus-induced memory loss could accumulate over the lifetime of an individual and eventually lead to clinical cognitive memory deficits,” according to Charles L.
Howe, Ph.D., a Mayo Clinic neuroscientist and corresponding author of the study.
Picornaviruses are the most common infectious viral agents in humans. They are a family of viruses that include rhinoviruses, which is a virus associated with the common cold; enteroviruses, a virus associated with respiratory and gastrointestinal ailments; encephalitis, inflammation of the brain; myocarditis, inflammation of heart muscle; and meningitis.
In the study, mice were infected with Theiler’s murine (mouse) encephalomyelitis virus (comparable to the human poliovirus). Researchers looked for signs of spatial memory loss in the mice. Mice that contracted the virus had difficulty learning to navigate a maze designed to test various components of spatial memory. The degree of memory impairment, which ranged from no discernable damage to complete devastation, was directly correlated to the number of dead brain cells in the hippocampus region of the mouse’s brain.
Picornaviruses infect more than one billion people worldwide each year. Generally individuals contract two or three enterovirus and/or rhinovirus infections each year. In some cases the viruses get into the brain, and in some children these viruses can cause long-lasting brain injuries. “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,” Dr. Howe says.
The degree of brain damage in humans infected with a picornavirus infection is not known, but the evidence from the mouse study suggests this is an area of research that should be explored further.
MEDICA.de; Source: Mayo Clinic