President Bush gave federal health officials standby power to quarantine anyone suspected of being infected with a new, sometimes fatal lung disease that is spreading around the world.

Bush issued an executive order adding severe acute respiratory syndrome, or SARS, to the list of illnesses for which the government can order someone held to prevent contagion.

The move marks the first time in 20 years that the list of diseases subject to federal quarantine has been expanded. In 1983, the disease caused by the deadly Ebola virus was added. The last time anyone was detained in a federal quarantine was in 1963, to prevent the spread of smallpox.

Federal health officials have said repeatedly that they have no plans to quarantine anyone and that Bush's Friday action was just a precaution. But the order is the latest indication of the rising level of concern about SARS, which is suspected of having already sickened at least 115 Americans in 29 states, including two in Virginia.

Most of the cases have occurred among people who recently returned from parts of Asia where the disease is most common. No one has died, and for unknown reasons the disease appears so far to be less severe in this country. Worldwide, SARS is believed to have struck at least 2,353 people in 18 nations. At least 84 have died.

SARS causes a flu-like syndrome, marked by symptoms such as high fever, cough and breathing problems. At least 80 percent of patients recover spontaneously, but the rest get sicker. About 3.5 percent die. There is no known effective treatment.

Most of the cases have been in southern China, where the disease is believed to have first emerged in November before spreading to Hong Kong. From there, air travelers spread the disease around the world, prompting a global health emergency to contain the illness.

-- Rob Stein

Guards in protective suits man the entrance of an isolation camp for residents evacuated from a Hong Kong apartment complex because of the disease's spread there.