The outbreak of severe acute respiratory syndrome (SARS) seems to have peaked in Canada, Hong Kong, Singapore, and Vietnam, according to the World Health Organization. Worldwide 5242 cases and 321 deaths were reported by 28 April in 28 countries, and concern is growing that the disease will become endemic in some countries if it is not brought under control soon.

However, in 23 countries the disease has been well contained, said Dr Mike Ryan, WHO's coordinator of the global outbreak alert and response network. “In a country like China, with a very large population, there is a possibility that disease can become established and remain in human populations, but we do have an opportunity to break the cycle of transmission in this disease and put it back in the box,” he said.

The numbers in China are expected to continue to climb in the coming weeks. “We think Beijing is a major, major black spot,” said Mr Peter Cordingley, spokesman for WHO's Manila office. By 27 April 1114 cases and 56 deaths had been reported there, and Beijing looks …