The Italian physician who first recognized that the world was facing an outbreak of a mysterious pneumonia-like illness died yesterday in Vietnam.
Meanwhile, the disease - called severe acute respiratory syndrome, or SARS - continued to spread, with 58 new cases in Hong Kong alone, some of them in residents of a single floor in an apartment building.
Public health authorities in Singapore expanded a quarantine to more than 1,500 people.
Canada closed a second hospital where health care workers had been exposed to the virus.
The World Health Organization urged the most heavily afflicted countries to begin screening departing airline passengers for symptoms of the illness.
And the U.S. Centers for Disease Control and Prevention expanded its warning against unnecessary travel to Singapore, China, Hong Kong and Vietnam.
The WHO said that, as of early yesterday, there were 1,553 suspected cases of the disease in 13 countries and 54 deaths. China remained the most heavily affected, with 806 cases, followed by Hong Kong with 470, Singapore with 89 and Vietnam with 58.
The United States had 62 suspected cases, but there have been no deaths. Canada had 37 probable cases and 36 suspected cases, with three deaths.
"Our biggest unknown is what is going on in China," which has been tight-lipped about epidemic-related events, said Dr. Julie L. Gerberding, director of the CDC.
"We're desperate to learn more about the scope and magnitude of the problem there. That will be the biggest predictor for where this [epidemic] will go over the next few weeks."
On Wednesday, China revealed that it had had more than 800 cases of SARS and 34 deaths, well beyond the 300 cases and five deaths it originally reported.
Chinese officials said Friday that they would begin making daily case counts and fatalities available electronically to health agencies but that it would take several days to get the system online.
The most recent fatality from the disease was Dr. Carlo Urbani, 46, an expert on communicable diseases who had worked in WHO programs in Cambodia, Laos and Vietnam. Urbani diagnosed the illness in an American businessman who had been admitted to a hospital in Hanoi, Vietnam. The businessman later died.
Because authorities did not realize at first that they were dealing with such an infectious illness, few precautions against its spread were in place, and 56 percent of the health workers who came in contact with the man developed SARS - accounting for nearly half the cases in that country.
Because of Urbani's early efforts, WHO officials said yesterday, global surveillance was heightened and many new cases were identified and isolated before they could infect other hospital staff.
Urbani was married and was the father of three children.
"Carlo Urbani's death saddens us all deeply at WHO," said Dr. Gro Harlem Brundtland, the agency's director-general. "His life reminds us again of our true work in public health."
Outside mainland China, the effects of the epidemic have been felt most severely in Hong Kong, where thousands of residents are wearing face masks or staying home. The Hongkong & Shanghai Banking Corp. shut part of a floor at its main office yesterday after a worker became ill, and the Bank of China closed a branch for thorough cleaning after a staff member there developed symptoms.
Anti-war demonstrations have been called off, the Rolling Stones have canceled appearances in China, and some airline crews have been wearing masks during flights.
The biggest concern was the new cases among residents of the Hong Kong apartment building. Although authorities have released few details, experts fear that it could mean the disease is creeping into the general community. So far, virtually all of the cases have been attributed to prolonged and direct contact with victims, as most cases occurred among health workers and family members of victims.
But seven previous cases were known to have occurred among people who stayed on one floor of a Hong Kong hotel. Singapore Airlines also said Friday that a flight attendant on the flight that carried a Singapore physician to Germany, where he was quarantined with SARS, has developed the disease.
Thomas H. Maugh II writes for the Los Angeles Times, a Tribune Publishing newspaper.