Boon Ping Chee, a physician at Tan Tock Seng Hospital, donned an N95 respirator mask, a disposable gown and gloves, put a stethoscope to a young man's chest, then studied a set of chest X-rays on a light box.

K.C. Ho, a 21-year-old Singaporean Army soldier, had a temperature of about 99 degrees Fahrenheit. His case was suspect because his sister worked at another hospital where severe acute respiratory syndrome, or SARS, had been reported. In addition, Ho recently attended a wedding in Malaysia where he met relatives from China, where SARS surfaced last year.

Boon said Ho's lungs sounded clear and his chest X-ray was negative. His fever was minimal. Ho said his sister and relatives from China were well. Boon said he was free to leave.

"That's a relief," Ho mumbled through his mask.

The exam was one about 200 SARS screenings conducted daily in a comprehensive attempt by the Singapore health department to eliminate the sometimes-fatal respiratory illness in this island nation. By checking all travelers when they enter the country by air and sea, and investigating cases of possible contact whenever they find them, Singaporean officials said they think it will halt infection even as new cases are reported throughout other parts of Asia.

So far, Singapore's "isolate and contain" SARS control strategy appears to be working, health officials said. While there were seven new cases yesterday, authorities said all are linked to previously known and isolated groups. But health officials are not yet ready to declare victory.

"SARS is an infectious disease," said Wilson Chong, attending physician in the hospital emergency room. "If you don't come into contact with an ill patient, you won't get SARS. We hope to break the chain of infection."

The exam today was taking place in Area C, Tent 6 of the screening area on the grounds of the hospital, which has been designated to handle all SARS cases.

If Ho had needed further observation, he would have been admitted to one of the hospital's SARS wards, where visitors are not allowed. Three teams of doctors and nurses tend to patients at the hospital, each team working in isolation -- including separate secretaries, radiologists and nurse aides.

Tan Tock Seng Hospital is slowly discharging non-SARS patients, and is not accepting other types of new patients. When SARS cases are detected elsewhere, they are sent here.

Currently, there are 62 people hospitalized for SARS symptoms, 16 of them in the intensive care unit. About 170 more non-SARS patients are still at the hospital. Slightly under half the hospital's 38 wards are devoted to SARS.

The hospital was able to gear up quickly for SARS in part because it had a mass disaster plan adopted after the terror attacks in the United States on Sept. 11, 2001, Chong said.

Chong said, however, that the hospital staff feels the pressure of the work it is doing.

"Now, whatever you do, it affects the whole nation," Chong said. "We can't let anyone who we think is infectious slip through our screening process or he will become a source of infection. That by itself is a big stress."

In the emergency room, Chong and his team are accustomed to trauma, and are equipped to treat accidents involving multiple victims. "But this is very different," he said. "It's like an alien movie where things propagate by themselves."

The concern is felt throughout Singapore. There are frequent calls to the hospital from people who fear a sudden cough means they could die from SARS, Chong said. And the doctor said his social circle has shrunk; some people are afraid to associate with him. Taxi drivers are reluctant to drive to the hospital.

"The shadows start to grow inside you," Chong said. "But you learn to rationalize it. You learn that it's natural for one to have fear."

At the same time, the hospital has been praised for its work. There is a display of thank-you cards on a lobby wall. "You're our war heroes in the war against SARS," reads one card. Patients and well-wishers have sent red roses, flower arrangements and cakes.

One key part of the isolation program involves controlling travel in and out of the city-state of 4 million people to Malaysia, to the north. While Singapore has reported 158 cases and 12 deaths since the SARS epidemic began, Malaysia has had only four cases and no new cases since last week.

This weekend at the border crossing, a half-hour drive across a causeway, nurses in the Malaysian state of Johor Baru wore face masks as they distributed SARS leaflets and collected health information cards.

On Sunday, four young Chinese women were stopped and asked to submit to a health exam. "Any of you have fever or a cough?" asked Rezudden Muhammad Noor, a doctor with the state health department. He took their temperatures, listened to their lungs. He pronounced them healthy.

But a few minutes later, they were stopped by immigration agents. Most Chinese citizens cannot enter Malaysia. A new regulation that took effect last week bars citizens from SARS-affected Hong Kong and China from entering the country unless they are expatriates or arriving for business or study, Malaysian immigration and health officials said.

Singapore is not a problem, said Praphapa Senan, the health director in Johor Baru. "Singapore's a good example of good control," he said. "If other countries can follow what they've done, I'm not worried about Singapore. I'm worried about Hong Kong."

A man reads posted messages thanking health workers who cared for SARS patients. Singapore has adopted a vigorous screening program to eliminate the disease.A man enters a screening room at Singapore's Tan Tock Seng Hospital, the designated site for isolating and treating the SARS respiratory ailment.