The severe acute respiratory syndrome (SARS) epidemic has been one of the most dramatic transnational infections of recent times. Images of entire populations of countries carrying on their daily activities with facemasks have perhaps no precedent in the history of man's struggle against infectious disease, except in science fiction movies. Inevitably, there has been a scientific debate surrounding the exact origin and nature of the virus, which will go on for some time. At present, the epidemic seems to be on the wane.