These farmers have Parkinson’s disease – and claim a weedkiller is to blame

One pesticide popular with US farmers has been prominently linked to the disease: a weedkiller called paraquat

• Secret files suggest chemical giant feared weedkiller's link to Parkinson's disease

When Illinois farmer Ron Niebruegge was diagnosed with Parkinson's disease at the age of 55, he was certain it must be a mistake. Niebruegge had always been healthy and active, someone who loved trail riding his horses and taking his wife dancing on weekend nights.

But a dizzy spell and a fall in 2007 led him to visit a neurologist, and then another. Both doctors agreed that the little things Niebruegge had started to notice - a left arm that didn't seem to work quite right, some stiffness in his joints - were undeniable signs of the onset of Parkinson's, a progressive debilitating brain disease for which there is no cure.