A Singapore man has been confirmed to have Severe Acute Respiratory Syndrome (SARS), raising the specter of another outbreak of the virus. It is the first known new SARS case since the World Health Organization declared the region's SARS outbreaks over several months ago.

Singapore's Department of Health on Tuesday confirmed that a hospital laboratory technician has contracted Severe Acute Respiratory Syndrome. It is the city-state's first new case since the World Health Organization declared Singapore SARS-free on May 31.

Doctors say the man, in his early 20s, had not traveled recently or come into contact with SARS patients. At least 25 people who had been in contact with the man have been isolated.

But Singapore's Acting Minister of Health Khaw Boon Wan told reporters that so far the man's contacts are not sick. "We are still checking to isolate the source of infection," said Mr. Khaw. "His contacts - we have largely tracked them down and they are well."

Doctors say the man has displayed fever and rash but none of the other symptoms associated with SARS. One important characteristic found in most SARS patients is swollen lung tissue, which causes pneumonia.

The case has raised alarm that the region may face a fresh outbreak of the disease.

Health authorities in Hong Kong, which reported a high number of cases earlier this year, warned hospitals to take extra care in handling patients with fever or respiratory illness.

"Hong Kong anticipates that SARS can come back," Health Department director P.Y. Leung told reporters on Tuesday. "We are all geared up for prevention."

Health checks at the Hong Kong airport have also been stepped up.

The Singapore man tested positive for SARS when the doctors used at least two different tests. One test checks for antibodies to the SARS virus while the other confirms the patient has fragments of the virus in his blood or secretions.

Despite the results, the WHO and Singapore's Acting Minister of Health Khaw Boon Wan say the case does not pose a significant threat to the public. "The WHO has informed us that this case does not fulfill their case definitions for SARS," said Mr. Khaw. "Our own assessment is that this case poses a very low public health risk as the patient was picked up and isolated very early."

The WHO says two cases of SARS must be found before it declares the illness to be SARS.

The disease first caught the attention of the media when it spread from southern China to Hong Kong and was carried overseas in March. In the months that followed, SARS infected about 8,000 people in more than 30 countries. About 900 SARS patients died.

The WHO and many governments warned travelers to postpone visits to affected areas, including Hong Kong, Singapore, mainland China and Taiwan. As a result, the tourism industry in the region suffered an acute downturn.