LAS VEGAS -- In Room 519 of Kindred Hospital, Linda Rivera can no longer speak. Her mute state, punctuated only by groans, is the latest downturn in the swift collapse of her health that began in May when she curled up on her living room couch and nonchalantly ate several spoonfuls of the Nestlé cookie dough her family had been consuming for years. Federal health officials believe she is among 80 people in 31 states sickened by cookie dough contaminated with a deadly bacteria, E. coli O157:H7. The impact of the infection has been especially severe for Rivera and nine...