Reuters reports on evidence that pesticides can cause Parkinson's disease.
One study shows that farm workers who used the common weedkiller paraquat had two to three times the normal risk of Parkinson's, a degenerative brain disease that eventually paralyzes patients.
A second study shows that animals exposed to paraquat have a build-up of a protein called alpha-synuclein in their brains. This protein has been linked to Parkinson's in the past.
A third piece of the puzzle shows that this buildup of protein kills the same brain cells affected in Parkinson's.