Severe acute respiratory syndrome (SARS) is a serious, infectious, pulmonary illness. As of April 8, 2003, the WHO reported a total of 2671 cases of SARS in 17 countries, with 103 deaths. The mortality rate is 3.9%. The probable etiological agent is a previously unrecognized coronavirus. The coronavirus has been found in at least 10 laboratories, including those of the CDC. Images of this new coronavirus can be viewed at http://www.who.int/csr/sars/coronavirus/en/ on the CDC Web site. Coronaviruses are the second most prevalent cause of the common cold (rhinovirus is the first).

The disease typically begins with a high fever and mild respiratory symptoms; some have reported chills, headaches, fatigue, and diarrhea. After 3-7 days, symptoms include a dry, nonproductive cough or dyspnea. In 10%-20% of cases, the respiratory illness is severe enough to require mechanical ventilation.

The WHO organized a network of 11 laboratories in 9 countries with the expressed purposes of detecting the SARS etiologic agent and developing a diagnostic test. In addition to being part of this network, the CDC is providing health alerts to those traveling to SARS-affected areas and meeting planes returning from SARS-affected areas to provide disembarking passengers with health alert notices.