Taking the recent anthrax scare as a warning, Baltimore and Maryland health officials are busy planning for a far graver threat - smallpox.
Plans being drawn up by the city and state health departments call for drastic measures to contain a potential epidemic that, if left unchecked, could spread to thousands of people.
Though the plans are incomplete, officials envision large-scale vaccinations, temporary bans on public events, isolation of patients and appeals for some people to stay home until the danger passes.
"I think that it is very, very unlikely that there will be a bioterrorism release of smallpox in the city of Baltimore and even in the region," said Dr. Peter L. Beilenson, the city's health commissioner. "But the consequences of this happening are so serious that we're irresponsible as public health officials if we don't prepare."
Dr. Georges Benjamin, the state health secretary, said smallpox is the bioterrorist weapon "that would tax our public health infrastructure the most."
In one of history's greatest public health triumphs, smallpox was eliminated from the globe in a decade-long campaign that ended with the isolation of the last case in Somalia in 1978. The disease was by most accounts the worst pestilence ever faced.
The Soviet Union later mass-produced smallpox as a weapon. Samples of the virus are kept in secure freezers in the United States and Russia, but bioterrorism experts have warned that rogue nations and terrorist organizations may be holding smallpox as a biological weapon.
Unlike anthrax, which is not transmitted from person to person, smallpox is highly contagious and could spread to hundreds or thousands of people before authorities were alerted to the danger.
Last month, the Centers for Disease Control and Prevention issued a draft plan that outlined the nation's response to a smallpox outbreak. Among other things, the agency said the main containment tool would be "ring vaccination" - the strategy that was used successfully in the global campaign.
The technique involves quickly spotting the first patients, isolating them in their homes or hospitals, and vaccinating others who might have come into contact with them. This in effect creates a protective ring around infected people.
Meanwhile, the CDC said it would consider large-scale quarantines, such as closing off an entire city, as a last resort if the disease seemed to be spreading out of control.
The federal government is setting the overall strategy for smallpox containment, but it is leaving many of the fine points to local health agencies.
Benjamin said the state's plan was a work in progress and could be completed by year's end.
Beilenson spoke in greater detail, but acknowledged that Baltimore's plan was still being developed.
Beilenson said the first smallpox patients could be placed in isolation rooms, but the few that exist in area hospitals would quickly fill up. Hospitals could place additional patients elsewhere, but would have little space, since most operate at close to capacity.
Any hospital admitting smallpox patients would have to vaccinate most if not all its patients and employees, he said.
The state, said Benjamin, has asked hospitals to tell him how much space they would have for a sudden influx of patients. Hospitals, he said, might be able to make additional room by canceling elective surgeries but probably couldn't accommodate everybody if the number of patients swelled into the hundreds.
Nursing homes, hospital ships and military hospitals also could be used, Benjamin said. He and Beilenson agreed that many patients would probably stay at home under the care of family members and, in some cases, visiting nurses.
Several city schools, said Beilenson, could be transformed into "triage, transport and treatment centers" - places where family members and others at risk could come to get vaccinated and pick up face masks.
Health officers would work to track down infected people and their contacts, but might find that the infection had spread too widely for ring vaccination to be feasible. Instead, the city might be better served by vaccinating virtually everyone. "The ring vaccination would almost be a ring around the city," he said.
Beilenson said he couldn't imagine cordoning off Baltimore, but would rely instead on rapid vaccination to contain the epidemic. Commuters and tourists, for instance, would have left by the time a quarantine was imposed.
The federal government has 15.4 million doses of smallpox vaccine, but recently signed a contract with a British pharmaceutical company to purchase enough vaccine to inoculate every American.
Federal officials have said the vaccine should be given only if an outbreak occurs. Most experts agree that in the absence of an actual attack, it is not worth exposing people to possibly severe side effects.
The CDC recently vaccinated about 100 of its employees so they could safely respond to an attack. State officials have argued that local health officers, paramedics and police officers should be vaccinated as well, since they would respond first in an emergency and face a greater danger of infection.