Parkinson’s disease. II. The beginnings of an answer?

In a recent article (see On Parkinson’s, paraquat, and probability), I discussed Parkinson’s disease (PD). My focus was on a recent claim by a respected reporter, Nicholas Kristof, that argued that increasing use of the pesticide paraquat might be responsible for the increasing incidence of PD cases. I argued that while paraquat and other herbicides mig…