WASHINGTON – Though potentially dangerous bacteria were detected late last month in the National Mall area, where tens of thousands of people from around the country had gathered for a book festival and an anti-war rally, public health officials in Maine and other states were not notified for five days.

Department of Homeland Security officials defend the delay, stressing that while the bacteria that cause the disease tularemia are considered a potential biological terror weapon, the samples did not meet the standards required to set off an immediate alert.

No cases of tularemia have been reported, and disease specialists say there is no longer any public health threat, but the incident has raised concerns about when the federal government should notify state and local public health officials of potential bioterrorist attacks.

“There should have been a much more rapid notification of the [Centers for Disease Control and Prevention] by the Department of Homeland Security, [and] in turn the CDC should have quickly notified the local health authorities,” said U.S. Sen. Susan Collins of Maine, chairman of the Homeland Security and Governmental Affairs Committee.

“Just imagine if there had been a biological release and the sensors had picked it up and we had lost five days in potentially identifying and providing early treatment to victims. That would be a terrible situation,” she said.

On Sept. 24, specially designed air monitors collected what later were identified as traces of Francisella tularensis in and near the National Mall area between the U.S. Capitol and the Lincoln Memorial. The bacteria occur naturally in the soil but also are considered a potential weapon of bioterrorism along with anthrax and smallpox.

About 250 people from Maine were in Washington on Sept. 24 attending the anti-war protest.

Tularemia, or what commonly is known as “Rabbit Fever,” is not spread from person to person but can be contracted from animals or insects. In rare instances – or if collected in a powder and sprayed into the air, as would occur in a case of bioterrorism – the bacteria can be inhaled. Symptoms can include fever, chills, headache, muscle aches and pneumonia. The disease is generally treatable, but is not always immediately recognized by doctors. It can be fatal if left untreated.

U.S. Rep. Tom Davis, R-Va., chairman of the Committee on Governmental Reform, wrote letters to the Department of Homeland Security and the CDC in early October to find out why public health officials in Washington, D.C., Maryland and Virginia were not notified sooner.

“If the bacteria detected can cause a flu-like illness and if symptoms can begin to appear one day after exposure it appears that notification of the appropriate state and local officials was delayed too long,” Davis wrote.

Dr. Jeffrey Stiefel, the program manager for BioWatch, a $60 million early warning, environmental monitoring program overseen by the Department of Homeland Security, disagreed. An initial test of the air samples done at a local laboratory on Sunday, Sept. 25, did not meet the standards for a “BioWatch positive,” he said.

“You’ve got to think of the greater good on this one,” he said. “If you come out and say that this is what it is and you’re wrong and the entire public health response network stands up, then you now … have that community losing faith and potentially nationwide losing faith in the system.”

Sen. Collins disagreed. “I supported the decision by New York officials to heighten security on the subway systems in response to what appeared to be credible evidence of a specific threat targeting the New York subway system,” she said. “Now it turned out that nothing happened, but I think it is better to be on the safe side.”

BioWatch is a system of air collectors whose filters gather samples daily in 30 U.S. cities. No BioWatch collectors are located in Maine. The samples are lab-tested the next day for six undisclosed substances in each of the cities except Washington, where they are examined for eight substances, according to Stiefel.

The results for lab tests done in Washington on Sept. 25 “didn’t meet our standards [for an immediate alert] because … there are a certain number of markers that have to show up every single time, and we weren’t getting that, but we were getting some of that which we’ve never seen before,” Stiefel said.

“Now is there a chance that you can miss something? Maybe,” Stiefel acknowledged. “But the fact is that if this had been … a true bioterrorist attack when they had used a lot of agent, it would have hit all of our markers … and we would have known by Sunday.” He added: “The system worked, and it worked better than one would have thought.”

A “very astute” lab worker encouraged a repeat test on Wednesday, after which the lab contacted the CDC for more sophisticated testing, even though it is not required to do so, Stiefel said. The CDC confirmed the fragments were of Francisella tularensis.

Though the bacteria most commonly are found in soil and water in desertlike areas such as in the Southwest, it has been reported in other parts of the country, such as Martha’s Vineyard in Massachusetts, where gardeners and landscapers have been diagnosed with tularemia. “They stir up dirt where an animal carrying it has died and created a sort of aerosol of it,” said Dr. Larry Madoff, a Boston-based infectious disease specialist.

One theory about what happened in Washington, according to Stiefel and Gregg A. Pane, Washington public health director, is that the protesters marching in the anti-war rally stirred up dust and naturally occurring particles in the environment.

Such an incident occurred in 2003 in Houston, where tests on an air sample showed fragments of Francisella tularensis after winds stirred up dust, according to Penny Hitchcock, senior associate of the Center for Biosecurity at the University of Pittsburgh Medical Center.

Stiefel, however, does not rule out the possibility of a terrorist attack. “We don’t know,” he said. “There’s no way that anybody can know. There’s not enough data.”

Whatever the cause, public health officials seem to agree that because there have been no reported cases of tularemia and the incubation period that can be as long as 14 days has passed, there is no longer a public health concern.

“It’s certainly been enough time that there would have been cases if there were cases, but we really don’t have a sense of how much was there and whether it was enough to cause disease,” said Madoff.

In response to criticism about BioWatch’s operating procedures, Stiefel said if the tests had resulted in a true “BioWatch positive,” notification would have gone out immediately. Also, the response given to something that is not a confirmed “BioWatch positive” differs depending on the organism. “One would think that if we had seen a similar signal and it said smallpox it would have gone up the chain real, real fast,” Stiefel said.

As it was, a nationwide alert was not sent out to state and local public health departments until Friday, Sept. 30, five days after BioWatch labs first detected the microbes.

Though symptoms of tularemia most often present themselves within one to six days, CDC officials wanted state and local public health officials to be on the alert for any signs that might show up as late as 14 days after exposure to the bacteria, said Von Roebuck, a CDC spokesman.

Maine state health officer Dr. Dora Mills said that when she received the alert on Sept. 30, “I was just sort of scratching my head.” The alert provided little information about the level of risk involved. “I had to read it twice to wonder what they were trying to get us to do,” she said.

Mills said she forwarded the alert to Maine infectious disease specialists, but did not try to track down the Mainers who had been in Washington that weekend.

Mainers who participated in the anti-war rally apparently have found out about the potential biological threat through media reports and word of mouth.

“Everything that we’ve read really [is] so preliminary,” said Merry Segal, a Bowdoin College sophomore who attended the anti-war march and helped organize buses for the event. “It’s something that we’ll follow but … we’re not doing anything at this point in response to it other than making other folks aware.”

“As we do more and more sampling of the environment we’re going to … detect organisms that are in the soil and that we didn’t know could be aerosolized and collected in a device like this, so there’s a learning curve,” said Hitchcock of the Center for Biosecurity.

“It’s a microbe that’s carried by rodents and other animals like rabbits,” said Mills. “It just would seem to me like of course you’re going to find it if you go looking for it on a grassy park.”