Alzheimer’s is considered the most common form of dementia. Now researchers suspect a certain virus may be causing the disease.
Around 1.8 million Germans are currently suffering from dementia. The number is expected to rise to 2.8 million by 2050. The most common form of dementia remains Alzheimer’s disease. The exact causes have not yet been clarified. One thing is certain: In those affected, certain protein accumulations (plaques) disrupt the communication between nerve cells. This results in memory and language disorders as well as impaired perception and spatial and temporal orientation.
US researchers have now discovered a surprising connection between Alzheimer’s and a herpes virus. Most people come into contact with the cytomegalovirus (CMV) during childhood and it is widespread worldwide. It usually causes no or only mild symptoms (such as a mild fever or cough). However, more dangerous illnesses can occur for immunocompromised people after an infection, including in newborns.
After an initial infection, the virus lies dormant in the human body. By the age of 80, nine out of ten people have antibodies detectable in their blood, meaning they have had contact with the virus.
Scientists have now found that in some cases the virus appears to remain active for a long time and moves into the brain via the vagus nerve. This nerve connects the gastrointestinal tract to the brain. Docked there, the active virus can damage the immune system of the thinking organ and thus contribute to the development of Alzheimer’s. It therefore promotes the production and deposition of amyloid plaques and tau proteins. In Alzheimer’s disease, these deposits clump together and cause the nerve cells to die.
“We believe we have found a biologically unique subtype of Alzheimer’s disease that could affect 25 to 45 percent of people with the disease,” says biomedical scientist and lead author Ben Readhead of Arizona State University.
The research therefore focuses on the group of people who suffer from a chronic CMV infection in the intestine. We are now working on a blood test that can detect the CMV infection in the intestine. Treating these patients with antiviral drugs may be an option to protect them from this type of Alzheimer’s.