SHARES
“HSV-1 could account for 50% or more of Alzheimer’s disease cases”, said Dr Ruth Itzhaki who dedicated over 25 years of her research at The University of Manchester to find a cure for Alzheimer’s disease.
What is Alzheimer’s disease?
Alzheimer’s disease is the most common form of dementia. This disease affects our brain function especially memory and navigation. To date, doctors are still looking for a cure to Alzheimer’s disease. It is still not entirely clear why some of us get Alzheimer’s disease while others don’t. The hallmark of the disease is a shrinking brain with abnormal protein, called “plaques” (beta-amyloid), depositing around the brain cells. Also, the small channels that help transport things around in a brain cell, called “microtubule”, are messed up and entangled (tau tangles). Researchers are looking deep at these amyloid plaques and tau tangles but still could not confirm the cause.
New Evidence on a Possible Cause for Alzheimer’s – the Herpes Virus (HSV-1)
Researches over the past 3 decades are pointing towards herpes simplex virus type 1 (HSV-1), or cold sore virus, as a possible cause for Alzheimer’s disease. Dr Ruth Itzhaki and her team, in their latest study in Taiwan, confirmed the link between herpes virus (HSV-1) infection and dementia. Majority of the these patients have Alzheimer’s disease. Although more specific studies are needed to confirm if herpes virus is causing Alzheimer’s, current evidence are show the link between the two for sure.
Likewise, studies over the decades proved that herpes infection on the brain can lead to deposition of beta-amyloid plaques as well as formation of tau tangles. These are the main brain changes seen in people with Alzheimer’s disease. Besides, researchers had noticed the anti-infective properties of these plaques earlier on, suggesting the possibility of plaque deposition as a body defence to fight off infection in the brain.
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What is HSV-1? How does it cause Alzheimer’s?
Herpes simplex virus type-1 is a common infection that causes painful blisters and ulcers in our mouth. This virus spreads through mouth-to-mouth contact (eg. kissing) and saliva. Most of the time, the virus hide in our nerve cells outside the brain (peripheral nerves) and we do not experience any symptoms. Only when our immune system is low (eg. during stress, illness, old age etc.), the virus becomes active again and we get painful ulcers in mouth. Sometimes, when the infection is severe, the virus can go to our brain and causes inflammation. Scientists believed that repeated reactivation of herpes infection throughout our lifetime can lead to accumulation of plaques, and hence, Alzheimer’s disease.
Antiviral Drug – A Possible Cure for Alzheimer’s disease?
Dr Ruth and her team found surprising result of lower rate of Alzheimer’s disease among those who received antiviral drugs for their herpes infection, including chicken pox (human herpes virus-3/ HHV-3). This points towards the the future possibility of preventing Alzheimer’s disease with antiviral therapy. However, the effective time, dose, duration and type of antiviral drug for preventing Alzheimer’s still need further research. Currently, we have no idea about the usefulness of antivirals for people without severe herpes infection as well as those who already have Alzheimer’s disease.
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Conclusion
Latest studies are showing a link between herpes infection and Alzheimer’s disease. Whether herpes virus is the cause or not is still not entirely clear. However, if future research can confirm infection as the cause, we might have a cure for Alzheimer’s disease!
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References:
1. Brian JB, Alan PH. Herpes viruses and Alzheimer’s disease: new evidences in the debate. The Lancet Neurology. 2018 Oct 1;17(10):839-841.
2. Pauline A. More evidenc herpes virus strongly tied to Alzheimer’s [Medscape]. WebMD LLC. [Available from: https://www.medscape.com/viewarticle/903703; last updated on 2018 Oct 19; last accessed on 2019 Jul 30].
by Chang Xian
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