A Possible Link Between Herpes and Alzheimer’s Disease

Eileen Bailey Health Guide
  • Although the cause of Alzheimer's Disease (AD) has been studied for many years, scientists still aren't sure about what may cause this debilitating and devastating disease. However, researchers have recently been looking at a possible link between the herpes virus (HSV-1) and AD.


    In previous studies, it was found that the brains of people with AD contained a large amount of a protein called beta amyloid. It was thought, therefore, that this protein was the cause of the disease. However, when the levels of this protein were decreased, symptoms did not improve and, in fact, increased.  In August 2010, Eli Lilly, the pharmaceutical company manufacturing a medication to reduce the levels of beta amyloid released a statement stating that studies showed this medication did not help patients with AD.

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    This left scientists trying to figure out why there are elevated levels of beta amyloid in the brains of patients with AD if it didn't contribute to the disease. A study completed at the Mass. General Hospital in 2010 may have, at least in part, an answer. According to the study beta amyloid may help to fight infections and levels may be high because patients have some type of infection. The researchers believe that the HSV-1, may be the infection the protein is trying to fight. This infection causes some genital herpes infections as well as common cold sores.


    A second study ["Seropositivity to Herpes Simplex Virus Antibodies and Risk of Alzheimer's Disease: A Population-Based Cohort Study,"] backs up these claims, showing that there is a high rate of HSV-1 in patients with AD. Ruth Itzhaki completed a study and her results were consistent, finding that HSV-1 was present within beta amyloid plaques.


    Having HSV-1 doesn't mean you will develop Alzheimer's Disease. There are many people with this virus that never show signs or symptoms of AD. However, the connection between these two is certainly promising in the search for the cause of AD. Screening tests for HSV-1 and properly treating it early may be an important step to decreasing the devastating effects of AD.




    "Herpes Simplex Virus Type 1 in Alzheimer's Disease: The Enemy Within," 2008, May, Ruth Itzhaki et al, The University of Manchester


    "Lilly Halts Development of Semagacestat for Alzheimer's Disease Based on Preliminary Results of Phase III Clinical Trials," 2010, Aug 17, Eli Lilly


    "Seropositivity to Herpes Simplex Virus Antibodies and Risk of Alzheimer's Disease: A Population-Based Cohort Study," 2008, Letenneur L, Pérès K, Fleury H, Garrigue I, Barberger-Gateau P, et al, PLoS One


    "The Alzheimer's Disease - Assoicated Amyloid Protein Is an Antimicrobial Peptide," 2010, Stephanie J. Soscia et al, Mass. General Institute for Neurodegenerative Disease and Department of Neurology, Mass. General Hospital


Published On: December 07, 2011