Reaction to recent editorials highlighting the role of viral infections and the risk of Alzheimer’s disease are currently trending on social media. Data indicate that individuals with herpes simplex virus type 1 (HSV1) or Chlamydia have an increased risk of developing AD (Itzhaki, R., et.al. 2016). Comments I have seen on social media are fraught with misinformation and over-interpretation.
We often think of Alzheimer’s disease as something that happens to other people but when we see risk that could directly affect us, our reaction is different. The fears expressed by some individuals through internet posts are likely unwarranted. An estimated 3.7 billion people under age 50 (67% of the global population) have HSV-1 infection (World Health Organization, 2016). However, only a relatively small fraction of the global population (47.5 million people) have dementia (World Health Organization, 2016).
There is significant evidence demonstrating associations between the role of viral infections and the risk of Alzheimer’s disease. At this point in time, however, most experts do not believe there is convincing evidence that viral infections are a causative factor in Alzheimer’s. So, in sum, we know viral infections increase the risk of AD but we do not know if they play a direct role in causing the hallmark symptoms of AD. This does not mean that this avenue of investigation is without merit. In my opinion, it means that we simply are not justified via the current evidence to say this is a causative factor in the development of AD. Stay tuned, as more data is generated scientists will be able to explain with greater certainty the role of viral infections and the risk of Alzheimer’s disease.
Itzhakim R., (2016) Microbes and Alzheimer’s Disease. Journal of Alzheimer’s Disease, Preprint, pp 1-6. March 8.
World Health Organization Website (2016) Media Center, January. Herpes Simplex Virus Type 1, Global Prevalence Rates; Global Dementia Prevalence and Incidence Rates. http://www.who.int/mediacentre/factsheets/fs400/en/
Dr. Morrison is a speaker with Jenerations Health Education and is well-recognized expert on Alzheimer’s disease. For 25 years, as staff and later faculty for the Johns Hopkins University School of Medicine, she served as Co-investigator for clinical drug trials, risk factor identification and caregiving issues related to dementia as well as published numerous peer reviewed journal articles and book chapters. In addition, she published a book with Peter Rabins MD for home caregivers. Concurrent to this experience, Dr. Morrison provided care for patients and families at dementia clinics located at Johns Hopkins, served as a mentor to several dozen graduate and undergraduate nursing students, medical students and social work students, trained the nursing staff of the Johns Hopkins Memory Center and Lakeside medical unit as well as provided consultative services to Faculty members and their patients at the Johns Hopkins Alzheimer’s and Memory Treatment Center. For the past 5 years she have served as Core Faculty at the Copper Ridge Institute, developing their dementia training curriculum and providing dementia related education to health care facilities on their behalf. In addition, as a dementia care consultant Dr. Morrison has written and provided dozens of continuing education programs for nurses, social workers, case managers, psychologists, health care administrators and presented them throughout the U.S.