Keeping SARS (search) from spreading in the United States is straining the already besieged public health system, and it's partly a matter of luck that this newest killer so far has been contained here.

The question is how long that luck will hold — and at what price. Health departments that already were struggling to deal with bioterrorism and West Nile (search) virus say their ability to protect against more common threats today is compromised.

"Critically important things are not being done," says Dr. Alonzo Plough, public health director for Seattle-King County, Wash.

The Centers for Disease Control and Prevention (search) is stretched, too, despite an emergency $16 million from Congress to fight SARS.

What if the anticipated summer resurgence of West Nile virus occurs at the same time as some other outbreak, perhaps food poisoning, and SARS is still around? Could CDC possibly handle it all, wonders Barry Bloom, dean of Harvard's School of Public Health.

And Dr. Georges Benjamin, head of the American Public Health Association, says, "Every crisis du jour ... forces tradeoffs, attention to one infectious disease at the expense of another."

Benjamin told members of Congress they play "a public health shell game" by funding CDC to handle one headline-grabbing problem at a time — anthrax, smallpox vaccinations, SARS — instead of paying for a seamless system that tackles everyday illnesses with a built-in capacity for emergencies, too.

And public health advocates question why the Bush administration's proposed budget for next year actually cuts some $52 million, by their tally, from CDC infection-control and disease-surveillance programs.

"These cuts did not make sense before SARS, and they certainly do not make sense in the midst of an emerging epidemic," Rep. Henry Waxman, D-Calif., wrote Health and Human Services Secretary Tommy Thompson. A Thompson spokesman promised to work with Congress "to get the right amount."

In stopping SARS, "we were lucky literally by days," says Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases.

The World Health Organization's March warning of SARS' appearance in Asia came in time for CDC to start catching sick travelers on incoming airplanes — and to tell doctors how to spot and isolate suspected patients before they spread illness.

More luck: The nation's first suspected case of SARS actually had arrived at a Leesburg, Va., hospital a month earlier, before doctors here knew a new disease was brewing. The woman was isolated two hours later because her nephew told an alert nurse that the patient had traveled to a Chinese province where relatives reported a mysterious pneumonia killing people.

So far, there are just 63 probable U.S. cases, of more than 7,300 worldwide.

Fortunately SARS struck this year instead of last: The $1 billion the government funneled to states last year to improve bioterrorism preparedness greatly helped their SARS response, says CDC Director Julie Gerberding.

But a huge crunch remains.

"I think we still do an adequate job, but we are having to prioritize on a daily basis," says Dr. Jonathan Fielding, public health director for Los Angeles County, where workers are balancing SARS with a major outbreak of antibiotic-resistant staph infections.

Seattle's Plough says it's like an undermanned fire department having to choose which burning building to save: Between SARS, smallpox vaccination, West Nile preparation and a major tuberculosis outbreak, he's almost $2 million over budget already. His swamped infection specialists have a backlog of hepatitis cases to investigate, and they can forget any work soon to fight some rapidly increasing sexually transmitted diseases.

All that's before summer mosquitoes bring back the worrisome West Nile virus, which killed 274 Americans last year.

In contrast, SARS so far hasn't killed anyone here — although a single missed case could cause a dire outbreak. Hospitals are struggling, often in vain, to make people understand they must call ahead if they fear they have SARS so they can be met and masked outside the emergency room — not walk inside and breathe on other patients.

Waxman and other lawmakers are pushing to rebuild the entire system instead of funding it crisis-by-crisis, so that public health is less dependent on luck. The wish list includes a $100 million infusion to improve detection of new diseases before they mushroom.

After all, "we will always be one plane ride away, one infected person away ... from a global tragedy," Benjamin says.