WASHINGTON • Every day, weekends and holidays included, epidemiologists at the St. Louis County Health Department monitor emergency rooms at more than 50 regional hospitals looking for evidence of a biological attack.

Software assembles patterns of fever, respiratory problems and gastrointestinal illness, potential signs that bacteria like anthrax or some other harmful agent is loose. Computer screens display color-coded trends of what doctors have seen: blue, if nothing looks unusual; yellow, if a pattern bears watching; and red, if investigation is warranted.

The monitoring is part of the region's defense against bioterrorism, a defense that may soon endure a loss of federal support in the drive to reduce the national debt.

The region's biosecurity system that has evolved since 9/11 and the deadly anthrax letters that followed also includes:

• The federally funded BioWatch program, which monitors for airborne pathogens at undisclosed sites. Filters removed daily are examined at public health offices for infectious agents;

• St. Louis County's Bio-Defense Network, in which more than 650,000 county residents would be given antibiotics in the event of an outbreak through participating businesses, schools and institutions.

Despite the preparations, local planners worry. The region's main federal source of anti-terrorism funds — the Urban Area Security Initiative Grant — was trimmed by 30 percent this year, and officials say they are getting strong indications that the Homeland Security grant will disappear altogether under cuts proposed in Congress.

"It's going to affect us drastically," said Nick Gragnani, executive director of the St. Louis Area Regional Response System, set up in 2003 to handle critical incidents in the bistate area.

St. Louis might consider itself lucky to have received $5.9 million this year from the federal program: 33 metropolitan areas, Kansas City among them, were cut off altogether in a redesigned grant with new risk criteria. The U.S. House has proposed further cuts that could dramatically change the program.

The grant, administered by the East-West Gateway Council of Governments, funds what is referred to as the terrorist early warning system, designed to speed coordination between law enforcement, fire departments, hospitals and other responders. The millions of dollars received thus far have created capabilities that extend to other potential disasters, from flooding to an earthquake, including five so-called heavy rescue squads.

The federal money has built a system for vital collaboration, said Gragnani, who spent 30 years with the St. Louis County Police Department.

"It knocked down the stovepipes and individual fiefdoms out there so everybody would not be responding individually," he said. "If the funding goes away, the concern is that everybody returns to the way it was."

The Homeland Security money also has been instrumental in forging coordination between hospitals for sharing information, staff and medicines.

"There are no Berlin Walls between us; we share everything," said Debbie Beezley, information manager at St. Anthony's Medical Center and a leader in the St. Louis Medical Operations Center.

The year-old center, funded by several government grants, is staffed by emergency preparedness professionals from health-care organizations in the region.

With the likelihood of less government money funneled to the region, local planners are considering how to proceed. Gragnani said that the Homeland Security grant has been marshaled in a way that can support the terrorist early warning system through 2015.

But planners said anticipated cuts will make two new initiatives harder to complete: a regional evacuation plan; and a network of medical shelters in the region where people could turn in a disaster or disease outbreak.

"It would hurt us, no doubt about it," said George Salsman, of SSM Health Care, co-chair of the response network's hospital preparedness group. "We have to move forward, so we would probably have to do things differently."

Greg Evans, who heads the Institute for Biosecurity at St. Louis University, worries about the region's decline federal support. His program — which doesn't get government money — conducts research and offers training in biosecurity and disaster preparedness at the undergraduate and graduate level.

Given his certainty that terrorists are pursuing biological weapons, Evans believes it would be unwise to cut back.

"But this is what we have a tendency to do," he added. "There hasn't been a major event over a period of time and therefore, it leaves people's consciousness and they move on to other things."