Updated interim surveillance case definition for severe acute respiratory syndrome (SARS)--United States, April 29, 2003.

CDC's interim surveillance case definition for severe acute respiratory syndrome (SARS) has been updated to include laboratory criteria for evidence of infection with the SARS-associated coronavirus (SARS-CoV) (Figure, Box). In addition, clinical criteria have been revised to reflect the possible spectrum of respiratory illness associated with SARS-CoV. Epidemiologic criteria have been retained. The majority of U.S. cases of SARS continue to be associated with travel, with only limited secondary spread to household members or health-care providers.