(USA TODAY) -- Acknowledging that SARS is probably here to stay, the World Health Organization will urge today that "health care facilities the world over" screen all patients with a fever and respiratory symptoms for the infectious pneumonia-like illness.

New guidelines set to be posted on the WHO's Web site will recommend that emergency doctors and nurses regard patients with these symptoms as "alert cases" who should be taken aside, examined, questioned about possible SARS exposure and placed in isolation if necessary.

"We cannot drop our vigilance," Mark Salter of WHO said in a conference call on Tuesday. "One individual with SARS who presents at a health care facility or within a community can cause a significant number of other infections, if he is not identified and isolated early."

WHO reported Tuesday that the agency has tallied 7,548 cases and 573 deaths since SARS, or sudden acute respiratory syndrome, emerged in China in November. The total in the USA is 64 probable cases and no deaths.

Emergency medicine experts say most hospitals in the USA have tightened their infection control efforts since WHO issued its global SARS alert in March.

"We're already doing that, and I think it's very appropriate," says Arthur Kellermann of Emory University and a board member of the American College of Emergency Physicians. "We started when we heard about the first cases of SARS."

Salter says doctors who examine possible SARS patients should stick to a strict set of universal precautions: wearing masks, gowns, gloves and goggles to protect themselves from the disease. SARS spreads readily among doctors and nurses caring for patients, though no new cases have been reported among doctors for weeks.

To make sure no doctor or nurse "takes shortcuts" with infection control precautions, he adds, someone should be assigned to monitor their behavior. Because protective clothing can be cumbersome -- although "not as cumbersome as people might imagine" -- health workers should be allowed to take breaks and work outside isolation units for a portion of each shift.

Kellermann says, however, that because of overburdened emergency rooms, not even the strictest precautions will prevent a SARS catastrophe if the disease breaks loose in the USA. A survey of about 1,500 hospitals by the General Accounting Office, the investigative arm of Congress, reports that hospitals handle more than 100 million emergency room visits each year.

One of every 10 hospital emergency rooms are so overcrowded that doctors divert patients elsewhere 20% of the time.

"Patients are stacking up in the emergency rooms," Kellermann says, adding: "If we don't have enough ER capacity to handle tonight's 911 calls, how in hell are we going to handle a widespread SARS emergency?"

Experts also worry that poor nations that lack even basic public health services will not be able to follow the new guidelines. Salter said WHO would try to help countries obtain the masks, gowns, gloves and goggles they need to protect patients and staff. China, he says, has ramped up production.

In another development, Kanchan Anand and his colleagues at the University of Lubeck, Germany, reported Tuesday in the online version of the journal Science that they have used genetic information from the SARS virus to create experimental protease inhibitor drugs, much like those used to treat AIDS. The drugs have not been tested in patients.

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