This is a carousel. Use Next and Previous buttons to navigateWASHINGTON — Americans returning from China landed at U.S. airports by the thousands in early February, potential carriers of a deadly virus who had been diverted to a handful of cities for screening by the Centers for Disease Control and Prevention.Their arrival prompted a frantic scramble by local and state officials to press the travelers to self-quarantine and to monitor whether anyone fell ill. It was one of the earliest tests of whether the public health system in the United States could contain the contagion.But the effort...…This is a carousel. Use Next and Previous buttons to navigateWASHINGTON — Americans returning from China landed at U.S. airports by the thousands in early February, potential carriers of a deadly virus who had been diverted to a handful of cities for screening by the Centers for Disease Control and Prevention.Their arrival prompted a frantic scramble by local and state officials to press the travelers to self-quarantine and to monitor whether anyone fell ill. It was one of the earliest tests of whether the public health system in the United States could contain the contagion.But the effort...WW…