An invisible threat?

As back-to-school season approaches, most parents worry about new clothes and notebooks. But they may not be thinking about a more serious back-to-school issue: pesticides.

New research shows that the number of children getting sick from pesticide exposure at school increased significantly from 1998 to 2002. Scientists hope the findings will inspire schools to seek chemical-free alternatives to control pests.

“At many schools, like the one my kids go to, an exterminator comes in and sprays every few weeks,” says Geoffrey Calvert, a doctor and epidemiologist with the Centers for Disease Control and Prevention in Cincinnati. Alternatives to chemical sprays include sanitation measures to discourage pests in the first place and screens and other barriers to keep bugs out. Exposure can come from pesticides used on school grounds or from chemicals drifting into classrooms from nearby farmland.

Calvert and colleagues analyzed data from 2,593 children and adults who reported acute illness after being exposed to pesticides at schools from 1998 to 2002. They found that while relatively few children became sick from exposure -- 7.4 cases per million school children in the U.S. -- rates increased from 5.6% in 1998 to 7.8% in 2002.

Although scientists are unsure of the reason for the increase, one possible explanation is the growing number of schools built near agricultural land. The research was reported in the July 27 issue of the Journal of the American Medical Assn.