There is some evidence that the infecting agent (bacteria? prions?) travels from the gut to the brain along the vagus nerve.

https://pmc.ncbi.nlm.nih.gov/articles/PMC5440238/

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lawlessone 6 hours ago | parent [-]

Sorry am i reading this wrong or does it suggest the opposite?

>Conclusions: Although overall vagotomy was not associated the risk of PD, we found suggestive evidence for a potential protective effect of truncal, but not selective, vagotomy against PD development.

	▲	pmdulaney 3 hours ago \| parent [-]
		You're right that the article seems to be talking out of both sides of its mouth, so to speak, as to the effectiveness of vagus nerve surgery. But the paragraph that begins with "Gastrointestinal symptoms" seems to conclude that the vagus nerve does play a role in the disease.