Pesticides and neurodevelopment disorders

A study of 72 mice mothers and their litters suggests a popular pesticide may cause neurodevelopmental disorders in humans. Previous studies have shown that nearly half of the risk for neurodevelopment disorders, including autism, is environmental, but few specific environmental causes have been clearly identified. James Burkett and colleagues exposed mice to low doses of  pyrethroid pesticide deltamethrin during pregnancy and lactation. Pups of exposed mothers vocalized less compared to pups of unexposed mothers. As adults, the offspring of exposed mothers showed reduced cognition and increased repetitive behaviors, including repetitive grooming and burying of marbles in cage bedding, compared with the offspring of unexposed mothers. However, there were no differences between groups in terms of sociality. Offspring of exposed mothers also had higher levels of striatal dopamine than the offspring of unexposed mothers. These results suggest that exposure to pyrethroid pesticides during development causes a behavioral phenotype in mice that is relevant to neurodevelopment disorders in humans, according to the authors. Pyrethroid pesticides are widely used in the United States and are found in most urban streams. Up to 70-80% of the US population has pyrethroid metabolites at detectable levels in their blood.