The scientists caution that more studies are necessary to explain the link, since it is probable that many factors contribute to a complex disease like Parkinson's. The researchers say it is unlikely that the pesticides on their own actually cause the disease. Cory-Slechta's team studied the effects of a mixture of two very common agrichemicals, the herbicide paraquat and the fungicide maneb. Each is used by farmers on millions of acres in the United States alone. Maneb is applied on such crops as potatoes, tomatoes, lettuce and corn.
Paraquat is used on corn, soybeans, cotton, fruit and a variety of other products.
The mice exposed to the mixture carried nearly all of the molecular hallmarks of Parkinson's disease as seen in humans. The environmental reality is that several of these chemicals are used on the same crops and in the same geographical locations. You've got to get rid of the weeds. Then the insects. The study is one of the first to examine the effects of such chemicals in tandem.