Cold Sores and Alzheimer's - The Connection
This month various news outlets have been trumpeting the announcement of an increased risk of dementia if you’re prone to cold sores. Like so many news announcements that sensationalize information the revelations to come out of Umea University in Sweden actually follow a track of research that has been going on for the past 25 years or so. So let’s take a more careful look at what’s going on.
The herpes simplex virus is extremely common and fairly easy to pass on. Herpes simplex type 1, is the agent responsible for the development of those irritating cold sores, and some estimates suggest that 80 percent or more of us carry it. Some people are regularly troubled by cold sore outbreaks and others aren’t but once the body is infected with the HSV-1 virus it never leaves and so far there is no cure.
The Umea University team is claiming that a reactivated herpes infection effectively doubles the risk of Alzheimer’s disease. The suggestion is that in elderly people with a weakened immune system creates the opportunity for the virus to spread to the brain, which starts the process leading to Alzheimer’s disease.
Previous findings to come out of Brown University in 2011, explains how the process might work. Cold sores commonly occur in the mucous membranes around the lips and mouth. Viral particles then have the opportunity to erupt from the cells and enter sensory nerve cells where they travel inside the nerve and towards the brain. The team actually watched the process unfold by tagging the virus cells with a green fluorescent protein and following its path. At that time, lead researcher Professor Elaine Bearer said, “it is no longer a matter of determining whether HSV-1 is involved in cognitive decline, but rather how significant the involvement is.”
An important risk factor for the development of Alzheimer’s is the ApoE-4 gene. It is estimated that around a quarter of the population inherits this gene, which carries a four-fold increased risk of the disease developing. The combined effect of ApoE-4 and the cold sore virus seems to be especially potent. Researchers at the University of Rochester Medical Center suggests ApoE-4 acts like a kind of welcome mat for the herpes virus allowing it to become more active in the brain.
Above all else these consistent findings seem to point to one thing and that is the need for effective antiviral treatments for those who may be at particular risk. Meanwhile Brown University researchers recommend people treat a cold sore as quickly as possible to reduce the time it actively travels around the body. The faster it is treated the quicker it returns to a dormant state.
Umeå University. (2014, October 20). Cold sores increase risk of dementia, research suggests. ScienceDaily. Retrieved October 30, 2014 from www.sciencedaily.com/releases/2014/10/141020104930.htm