Published March 26, 2013
Herpes simplex - the virus that causes cold sores - may seem like just a nuisance, but the infection may actually have an impact on cognition and memory in the long term.
A new study revealed that the herpes simplex virus, along with other viral and bacterial infections, may increase an individual’s risk of having cognitive problems. The research found those who had higher levels of these infections, to which they had been exposed for many years, were linked with more memory problems than individuals who had lower levels of infection.
According to the researchers, the idea to look at the connection between infection and memory revolves around the inflammation the viruses and bacteria can trigger in the body. Previous research has found this kind of inflammation is associated with developmental dementia and increased risk of vascular diseases such as stroke.
“The idea is that these pathogens - both virus and bacteria - they might affect blood vessel walls, leading to vessel inflammation within the brain, which is associated with vascular dementia,” lead author Dr. Mira Katan, with the Northern Manhattan Study at Columbia University Medical Center in New York and a member of the American Academy of Neurology, told FoxNews.com. “That’s one possible connection.”
“The other idea is that these pathogens are directly neurotoxic, meaning they might enter the brain and affect brain tissue and neurons directly,” she added.
Katan and her colleagues analyzed 1,625 people living in Manhattan with the average age of 69, measuring the amount of antibodies in their blood. They tested for three low-grade viruses - herpes simplex type 1 (oral) and type 2 (genital) and cytomegalovrius - along with chlamydia pneumoniae, which causes respiratory infection, and Helicobacter pylori, a stomach bacterium.
Following the subjects an average of eight years, the researchers administered tests for memory and thinking skills each year. Ultimately, the tests revealed that individuals with higher levels of infection in the body had a 25 percent increased risk of having memory problems than those with lower levels of infection.
“We found actually that a mathematical combination of all these pathogens is associated with cognition problems,” Katan said. “It’s not just one pathogen, but the cumulative burden of all these infections. So it’s bad if you have one infection, but it’s worse if you have several infections. This effect of several infections was associated with cognitive impairment.”
However, these infections were not associated with worsening memory and cognitive abilities over time.
Katan noted further research is needed to better establish this connection, but if these findings hold true in the future, then it could lead to a push for earlier intervention through vaccination.
“You might look for vaccinations in early childhood to prevent development of cognitive impairment,” Katan said. “You could treat them with antiviral medication to reduce this risk…It might have a big effect on the population if you could reduce risk for both stroke and cognitive impairment. You would have two major public health burdens you could address with a relatively simple thing like vaccination – if (the research) holds true.”