A Northwestern Medicine research lab has found a usually harmless virus in brain samples from Parkinson\u2019s patients. The idea that Parkinson\u2019s could be linked to a virus had been theorized for years, but this is the first study to pinpoint a specific virus as more common in Parkinson\u2019s patients.<\/p>\n
\u201cThe message that we want to give to the general public is, it opens a new field of investigation, something that we didn\u2019t know about,\u201d said Dr. Igor Koralnik, Northwestern\u2019s chief of neuroinfectious diseases and global neurology and lead author of the study.<\/p>\n
Parkinson\u2019s disease is a movement disorder caused by the loss of neurons that produce dopamine, a chemical messenger in the brain. Why these neurons break down is unknown, but it\u2019s thought that this breakdown is caused by many factors, both genetic and environmental.<\/p>\n
The team used a tool called ViroFind, which is able to test samples for all known viruses that infect humans much quicker than the usual one-at-a-time \u201cbrute force\u201d method. The lab found human pegivirus, or HPgV, in 5 of the 10 Parkinson\u2019s-affected brains they tested, and none of the brains without Parkinson\u2019s.<\/p>\n
\u201cFifty percent of any population having this virus would be very, very high,\u201d Barbara Hanson, the lab\u2019s post-doctoral fellow, said. Estimates calculate HPgV as being present in about 5% of blood donors in North America, and people with healthy immune systems generally lose the virus within two years of exposure. It is not known to cause disease in humans, so most who catch the virus will never know they had it.<\/p>\n
Before this study, Hanson said, HPgV had not been found in human brain tissue. It was understood to primarily \u201clive\u201d in blood.<\/p>\n
\u201cFor this virus to be present in the brain, there must be a reason for that,\u201d Koralnik said.<\/p>\n
This doesn\u2019t mean that the virus itself is a trigger for Parkinson\u2019s, though. It could be that an as-yet unidentified genetic mutation that makes people susceptible to Parkinson\u2019s, also allows for the virus to spread throughout the body differently than in people without the mutation.<\/p>\n
And even if further research shows HPgV as a direct cause of Parkinson\u2019s, both Koralnik and Dr. Danny Bega, medical director of Northwestern\u2019s Parkinson\u2019s Disease and Movement Disorders Center, said people shouldn\u2019t necessarily worry about getting HPgV.<\/p>\n
A patient likely has to encounter a couple of different factors before they develop Parkinson\u2019s, Bega said. He puts it in terms of \u201chits\u201d \u2014 a hit could be genetic, or it could be environmental, such as exposure to a virus or pesticide. These \u201chits\u201d build up over time until there are enough factors to cause the neuron degeneration specific to Parkinson\u2019s.<\/p>\n
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Barbara Hanson sorts through slides that contain slices of brain matter from patients with Parkinson’s disease, July 14, 2025, at Northwestern\u2019s Searle Medical Research Building. (Brian Cassella\/Chicago Tribune)<\/p>\n
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Barbara Hanson, Dr. Igor Koralnik and Xin Dang in their lab where their team does research on Parkinson’s disease, July 14, 2025, at Northwestern\u2019s Searle Medical Research Building. (Brian Cassella\/Chicago Tribune)<\/p>\n
![\"Barbara](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2025\/07\/ctc-l-nw-parkinsons-virus-08_231378982.jpg\")
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Barbara Hanson sorts through slides that contain slices of brain matter from patients with Parkinson’s disease, July 14, 2025, at Northwestern\u2019s Searle Medical Research Building. (Brian Cassella\/Chicago Tribune)<\/p>\n
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Barbara Hanson sorts through slides that contain slices of brain matter from patients with Parkinson’s disease, July 14, 2025, at Northwestern\u2019s Searle Medical Research Building. (Brian Cassella\/Chicago Tribune)<\/p>\n