ATLANTA -- U.S. health officials said Saturday that none of the antiviral drugs and other treatments they have tested are effective against a flu-like disease that has killed at least 54 people and sickened nearly 1,500 others around the world.
They also expanded their travel advisory, suggesting that anyone planning nonessential travel to mainland China, Hong Kong, Singapore or Hanoi, Vietnam, "may wish to postpone their trips until further notice."
"The global epidemic continues to expand," said Dr. Julie Gerberding, head of the Centers for Disease Control and Prevention. "We recognize this as an epidemic that is evolving."
The CDC has reported 62 cases of severe acute respiratory syndrome, or SARS, in the United States, and at least 35 cases have been reported in Canada, where three people have died.
But the majority of the cases have been in Asia, where the illness is believed to have originated.
On Saturday, the first doctor to realize the world was dealing with an unfamiliar disease died of the illness in Thailand. Dr. Carlo Urbani, 46, of Italy, a World Health Organization expert on communicable diseases, became infected while working in Vietnam, where he diagnosed a U.S. businessman hospitalized in Hanoi, the U.N. agency said. The businessman later died.
U.S. health officials believe the illness comes from a new form of coronavirus, the virus that causes about a fifth of all colds.
Gerberding said Saturday that no successful drugs or treatments had yet been found.
"We have no evidence that any specific antiviral, steroid treatment or other agents that are targeting this virus have any benefit to patients," she said.
Two possible diagnostic tests that detect antibodies, indicating a person's immune system has reacted to the virus, are under development, and CDC officials hope to soon be able to supply those tests to state health departments, CDC officials said.
In Hong Kong, the number of people suffering from flu-like disease increased sharply Saturday to 12 people killed and 470 sickened. Dr. Yeoh Eng-kiong, Hong Kong health secretary, said more residents likely will become sick. More than 1,000 have been quarantined.
Thousands of Hong Kong residents donned surgical masks but many others refused to venture out, and activity in the usually bustling city stopped. Schools were closed and some companies shut down after workers became sick.
Singapore, which has had two deaths, nearly doubled the number of people quarantined to more than 1,500 on Friday.
The illness appears to have originated in China, which has been criticized for being slow in reporting cases. WHO officials who went to China to investigate the disease said Beijing has promised to improve monitoring of the illness, with daily updates from every province.