The Chinese authorities have joined the global effort to discover the origin of the virus that has caused a worldwide epidemic of severe acute respiratory syndrome (SARS). A team of investigators from the World Health Organization was allowed into Guangdong province last week to examine records of the cases that had occurred there and to meet health workers.

WHO now cites southern China as the place where the virus emerged. A spokesman for the WHO team said that the evidence they had gathered pointed to the coronavirus as the most likely cause of the outbreak but that it was too early to say if there was any link between …