New virus linked to Parkinson's disease discovery raises questions

In a significant study released on July 8, 2025, by Northwestern Medicine researchers in the United States, a potential link between a common virus and Parkinson's disease was investigated. The research, led by Dr. Igor Koralnik, chief of neuroinfectious diseases and global neurology, focused on understanding whether environmental factors, specifically viruses, could be associated with the onset of Parkinson's disease in certain patients. Historically, the exact causes of Parkinson's have largely remained unknown, although genetics are known to play a role in some cases. To explore this hypothesis, Koralnik's team utilized a sophisticated tool named 'ViroFind,' which can identify over 500 different virus species in clinical samples. They analyzed brain tissue from ten deceased patients diagnosed with Parkinson's disease and compared it to samples from fourteen other control patients who died from unrelated causes. Notably, they identified the presence of Human Pegivirus (HPgV) in brain tissue samples of 50% of the Parkinson's patients, while it was absent in the control group. Furthermore, those Parkinson's patients who had the virus exhibited more severe pathology and unique changes in immune signaling in their brain tissues. In addition, the researchers conducted tests on spinal fluid samples from the deceased patients, confirming the presence of HPgV correlates in Parkinson's patients but not in the control group. Complementary studies involved blood samples from over 1,000 participants in the Parkinson's Progression Markers Initiative, which highlighted similar immune-related alterations associated with HPgV. Interestingly, the research identified variations in immune responses to HPgV among patients carrying the LRRK2 gene mutation, a factor known to be related to Parkinson's disease. While the presence of Human Pegivirus does not indicate causation, it opens a new field of inquiry into potential treatments for Parkinson's disease. The research suggests that existing antiviral medications, currently used to treat Hepatitis C, might be repurposed to target HPgV in the brain if further studies validate these findings. The implications of linking this virus to neurological conditions may lead to new therapeutic strategies in the future, emphasizing the significance of viral agents in the disease processes of neurodegenerative disorders. Further research will be necessary to establish how widespread HPgV is among Parkinson's patients and whether it indeed contributes to the disease's pathogenesis.