A medical researcher in Singapore was confirmed to be suffering from Sars yesterday in what appeared to be the world's first case since a global outbreak was declared over in July.
Health officials said a second test on the 27-year-old man, a laboratory technician, had proved positive and samples were being sent to the US Centres for Disease Control and Prevention in Atlanta, Georgia for further checks.
The announcement caused alarm throughout Asia and jolted the financial markets, shaving 2.6 per cent off the Straits Times index, its biggest one-day fall since March.
But the World Health Organisation said the case did not fit its definition of the disease under its new guidelines and would not pose a public health emergency. Under the WHO definition at least two people with clinical signs of the disease must be identified in the same environment to count as "probable" cases.
Singapore's Health Ministry said the sick man, a post- doctoral student investigating the West Nile virus at National University of Singapore, posed only a "low public health risk", because he had been isolated quickly. Twenty-five people who had had contact with him were in quarantine.
Khaw Boon Wan, the acting Minister for Health, said: "Regardless of what the WHO's definition is, I can't ignore the fact that this is a Sars case."
How the man caught the virus was unclear. He was not involved in Sars research, had no known contact with Sars patients and had not travelled outside Singapore recently.