Bioterror Sensors Yield Curious Findings
Correction Nov. 9, 2005
The Department of Homeland Security says that the Biowatch system detected the Francisella tularensis bacterium in Texas, not a close relative as reported.
RENEE MONTAGNE, host:
After the anthrax attacks in 2001, hundreds of sensors in major metropolitan areas were set up to detect a possible bioterror attack. The government has been secretive about the project, called BioWatch. New public research reveals the sensors are probably picking up some curious things. NPR's David Kestenbaum reports.
DAVID KESTENBAUM reporting:
The sensors are in undisclosed locations. They suck in air around the clock and pass it through a filter. Once a day, someone collects the filter and sends it to a lab for testing. The labs look for anthrax bacteria, among other things, and the test has to be very accurate. No one wants a false alarm that would shut down a building or put masses of people on medication.
Now if you want to prevent false alarms, you need to know what's out there in the air to start with. To try to figure that out, researchers at Los Alamos National Laboratory studied 15,000 air-quality filters from the Environmental Protection Agency. The filters came from 15 cities around the country, and not surprisingly, they held loads of bacteria, some surviving as hardy spores just like anthrax does. Cheryl Kuske is a microbiologist at Los Alamos.
Ms. CHERYL KUSKE (Microbiologist, Los Alamos National Laboratory): Every city had spores in the air. Every city had fungal spores. Every city had bacterial spores.
BRADY: We are all breathing in spores, harmless ones. It's well known that bacteria rule the world if you go by numbers.
Ms. KUSKE: In recent surveys, we have found that even in just one gram of soil, which is about the size of your thumbnail, you can have tens of thousands of bacterial species present there.
KESTENBAUM: The good news is that the team did not find anthrax bacteria in the air, or the bacteria that cause plague or tularemia. They did find some unusual things, though. For instance, in a nice Chicago suburb, a place with golf courses, they found bacteria with DNA that was a close match for anthrax, not anthrax, but an undiscovered, very close relative.
Ms. KUSKE: One of the most remarkable things we found was that we discovered many new species and types of bacteria in these survey samples that are related to pathogens that we never knew existed. And right now we can detect them by DNA-based methods but we don't know anything about their biology, so what remains to do is to separate them out individually and grow them in the laboratory so that we can study the different traits that they have.
KESTENBAUM: The team's work was presented at a recent conference in New Mexico. Phil Hanna, an anthrax expert at the University of Michigan, was there. He says the finding is surprising and a potential concern for the bioterrorism centers but not for people in the neighborhood.
Mr. PHIL HANNA (University of Michigan): I'd still play the back nine there at the golf course. But we live in a microbial world. If you work in the garden, there's the agents that cause gas gangrene in the soil. There's the agents that cause tetanus in the soil. There's probably the agents that cause botulism in the soil.
KESTENBAUM: Humans have good defenses against these things--hairs in the nose, mucus to filter out bacteria and an entire immune system at the ready. Martin Hugh-Jones, who studies anthrax at Louisiana State University, says the new finding is interesting because it offers a glimpse at how anthrax might have evolved. Scientists know anthrax has two major spore-forming cousins out there and that some of the genetic material is in rings called plasmids. They can hop from bacterium to bacterium. The new Chicago variant may be an example of the different pieces coming together.
Mr. MARTIN HUGH-JONES (Louisiana State University): That is one of the most fascinating things. It confirms that, hey, there's this bunch of ill-behaved cousins of anthrax out there in the soil. One of them got in the right plasmids and it was off as a killer. The rest were just muggers.
KESTENBAUM: The Department of Homeland Security is well aware of the potential for BioWatch to generate false alarms. Two years ago, one of the sensors in Houston, Texas, found what appeared to be tularemia bacteria, a potential bioterrorism agent. It turned out to be a close relative instead. Last month during a book fair and anti-war rally in Washington, DC, multiple collectors near Independence Mall also picked up a small tularemia signal. Officials say this one was real, but not a bioterror attack. Possibly the organism had been in the soil and got kicked up by the crowds. David Kestenbaum, NPR News.
MONTAGNE: This is NPR News.
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