As West Nile Virus marches westward across the country, local governments trying to manage the mosquito-borne disease with targeted spraying are up against another pesky force: residents. Although 25 Texans have been infected with West Nile, the pesticide trucks aren't rolling in Hays County, south of Austin. More than 500 people there have signed petitions complaining that the insecticides make them sick, and the county's $35,000 mosquito-control program is on hold. "It appears that there's some chemically sensitive people," says the county health department's Tom Pope. "They've been raising a lot of Cain." Officials in Houston's Harris County are having the opposite problem. Trucks there head out five or six nights a week, says Sandy Kachur of the county's public-health department, but residents want more. "Our hardest task has been letting people know we're not a pest-control company," Kachur says. "We're looking for disease." For both counties the stakes will probably rise. The Centers for Disease Control is predicting that human cases of West Nile, currently at 251, could reach as many as 1,000 by summer's end.