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Some researchers speculate that a "slow" virus could be the cause of alzheimer's disease. We examine this theory and determine if this is a possible cause or sympton of alzheimer.
Does a Virus or Bacteria cause Alzheimer's Disease
Cause of Alzheimers Disease
Some researchers speculate that a "slow" virus could be the cause of alzheimer's disease. A slow virus can lie dormant in the body for years. When conditions are favorable, the virus becomes active. Herpes simplex virus 1 [HSV-1] is the name given to the virus that causes cold sores on lips. HSV-1 is extremely common and lies dormant in virtually everyone. Sunlight or cold infections can activate the virus. The HSV-1 virus is a risk factor for alzheimer's disease. People with an apolipoprotein E4 gene are at increased risk for alzheimer's disease late in life. People who have both high HSV-1 viral exposure and an E4 gene have a 3-fold higher risk for alzheimer's disease than people with only the E4 gene or high HSV-1 expression [17,18]. The HSV-1 virus is an important risk factor for alzheimer's disease. To date, no other virus has been implicated as a risk factor for alzheimer's disease.
Bacteria can cause brain infection and dementia. For example, Treponema pallidum, the spirochete that causes syphilis, attacks the brain and causes a form of dementia in the late stage of syphilis.
Bacteria have been found in alzheimer brains. One study found filamentous Actinomycetes bacteria increased 4-fold in alzheimer brains, but not non-demented elderly[19]. Recently, a team at Hahnemann Medical University in Philadelphia, Pennsylvania, found evidence that only alzheimer brains were infected by a common bacterium called Chlamydia pneumoniae [20]. A follow-up study by another group did not detect any evidence of Chlamydia pneumoniae in the brains of alzheimer patients [21], so it seems this matter is still unresolved at this time.
