Authorities around the country have taken steps short of quarantines to try to contain the illness.
U.S. health authorities are handing out warning cards to travelers who arrive by plane or ship from Asia, including those who may have passed through infected countries. The cards advise them to monitor their health for at least 10 days because of possible exposure to SARS.
``If you become ill with fever accompanied by cough or difficulty in breathing, you should consult a physician,'' the cards say.
SARS prompted precautionary steps Tuesday at Syracuse University, which cut short a study-abroad program in Hong Kong and called home 31 students _ 15 Syracuse students and 16 from other colleges. The university in New York state also has decided to cancel two upcoming summer programs in mainland China.
In Greenwich, Conn., the Greenwich Country Day School asked more than 40 students and staff members to stay home for a few days because they had recently visited the Far East, some on a class trip. None of them have shown symptoms of SARS, the school said Tuesday.
``This is probably the most conservative position that any school in the United States is taking,'' said Headmaster Doug Lyons, who decided Sunday to have the students and staff stay home. ``A reasonable person might say, 'Doug you're overreacting,' and I would accept that and say, 'You may be right. Forgive me.'''
Thompson, who was touring a new CDC emergency operations center, said more pressure would be applied on China. The disease first unfolded there but was kept quiet for months.
Travel agencies, meanwhile, reported cancellation of trips to Asia.
At 5 Oceans Tours in Westminster, Calif., some customers have canceled flights to the continent, and weekly bookings for trips there have dropped from 100 to five, according to manager Cam Tsai.