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A Viral Cause of Parkinson's
There are so many causes of Parkinson-like symptoms that as a whole, they're known as Parkinson's Diseases. One that has puzzled scientists in recent years makes up about fifteen percent of the world's ten million cases. Now they've connected these cases to a shared trait: many are survivors of encephalitis from decades ago.
Encephalitis is brain inflammation. Scientists found that many survivors of the nineteen-eighteen Spanish flu who got encephalitis developed Parkinson's. Then in recent years they saw half the survivors of West Nile encephalitis and a quarter of Western Equine encephalitis survivors developed what is now called Viral Parkinsonism.
To explain this, they infected mice and found the animals lost nerve cells that make dopamine, typical of Parkinson's. MRI scans showed the virus in two brain structures involved in dopamine production. The mice had forty-six percent more microglial cells which are immune cells that fight viral infections as well as seventy nine percent more astrocytes. These cells promote energy and blood flow in neurons during infection. The mice brains also had alpha-synuclein protein clumps typical of Parkinson's.
Scientists think the surge of these immune cells in the brain may cause damaging inflammation. Combine that with less dopamine producing cells and years after encephalitis, some develop viral parkinsonism. Perhaps this new lead will produce much needed therapies.
More Information
Viruses can infect the brain, hide out for decades, and then cause Viral Parkinsonism
How do you study a disease that takes decades to reveal itself? In this case, scientists used mice, viruses, and a little immunotherapy...
Mayo Clinic Disease Information: Encephalitis
Encephalitis is inflammation of the brain. There are several causes, but the most common is a viral infection...
CDC: 1918 Flu Pandemic
The 1918 influenza pandemic was the most severe pandemic in recent history. It was caused by an H1N1 virus with genes of avian origin. Although there is not universal consensus regarding where the virus originated, it spread worldwide during 1918-1919...
