To secure early warning of a bioterror attack, the government is building a computerized network that will collect and analyze health data of people in eight major cities, administration officials say. The Centers for Disease Control and Prevention is to lead the multimillion-dollar surveillance effort, which officials expect to become the cornerstone of a national network to spot disease outbreaks by tracking data like doctor reports, emergency room visits and sales of flu medicine. "Our goal is to have a model that any city could pick up and apply," a senior administration official said of the plan. Officials would not...