Federal health officials on Friday expanded the scope of their investigation into an outbreak of a diarrhea-causing parasite to four additional states, broadening the size of the largest U.S. outbreak of cyclospora. The Centers for Disease Control and Prevention said the outbreak first tied to shredded lettuce served at Taco Bell restaurants now includes Illinois, Kansas, Oklahoma, and Pennsylvania. Previously the agency's investigation included five states: Indiana, Kentucky, Michigan, Ohio an