Parkinson's disease (PD) is a neurodegenerative disorder for which there is no cure. Most
patients suffer from sporadic PD, which is likely caused by a combination of genetic and
environmental factors. Braak's hypothesis states that sporadic PD is caused by a pathogen
that enters the body via the nasal cavity, and subsequently is swallowed and reaches the
gut, initiating Lewy pathology (LP) in the nose and the digestive tract. A staging system
describing the spread of LP from the peripheral to the central nervous system was also …