III.

How the Illness Spreads

Infection with SARS results from close contact with an infected person. SARS can spread if a person inhales droplets sprayed into the air when an infected person coughs or sneezes. SARS may also spread when a person touches an object that has been contaminated. Scientists are investigating if the infection can spread in other ways. Symptoms typically develop two to seven days after exposure, so someone may unknowingly become infected and spread the illness before developing symptoms. In Asia, before infection-control measures were established, many SARS cases occurred among hospital workers who cared for SARS patients. These infected hospital workers, in turn, spread the illness to people living in their households. Most SARS cases reported in Canada were in people who became infected with the illness while traveling abroad or people who were exposed to infected travelers from abroad.