Severe acute respiratory syndrome (SARS) is a highly infectious disease with a significant morbidity and mortality. Respiratory failure is the major complication, and patients may progress to acute respiratory distress syndrome. Health care workers are particularly vulnerable to SARS. SARS has the potential of being converted from droplet to airborne transmission. There is currently no proven effective treatment of SARS, so early recognition, isolation, and stringent infection control are the key to controlling this highly contagious disease. Horseshoe bats are implicated in the emergence of novel coronavirus infection in humans. Further studies are needed to examine host genetic markers that may predict clinical outcome.