The Centers for Disease Control and Prevention is still trying to figure out how the military managed to ship anthrax spores that were apparently live from one of its facilities to more than a dozen labs across the United States.
"We have a team at the [military] lab to determine what may have led to this incident," says CDC spokesman Jason McDonald. In addition, he says, the agency is working with health officials in nine states to make sure the potentially live samples are safely disposed of and the labs affected are decontaminated.
McDonald says four workers in three states are being treated for possible anthrax exposure. Separately, the military says that 22 individuals at Osan Air Base, a U.S. facility in South Korea, are also receiving treatment. The workers were apparently sent the samples — which where supposed to have been killed via radiation before being shipped — to use as part of routine laboratory training.
So far it appears nobody has gotten sick from the anthrax.
The anthrax spores were sent from the Army's Dugway Proving Ground in Utah to 18 labs around the country. The samples, which the military says were shipped commercially, were for use in determining whether a new detection test for anthrax and other organisms works as expected. But one lab in Maryland discovered that at least some spores in its anthrax sample were still alive. It reported the problem to the CDC late Friday night.
The incident is worrying, but not entirely surprising, says Paul Keim, a biologist at Northern Arizona University who studies anthrax.
"Anthrax is one of the most difficult microorganisms to kill," he says. The bacteria can survive for years in the form of tough spores. Once these spores get into the body of an animal or a person, the CDC says, the water, sugars and other nutrients there can activate the spores, turning them into active, growing cells.
The Army facility zapped the anthrax with radiation, which is supposed to render anthrax spores permanently inert. Obviously, Keim says, something went wrong: Maybe they didn't do it long enough to kill everything.
"One of the things that can happen is that they set it up, and they do it, and they find out later that it only kills 99.99 percent," Keim says. That's more than enough if you're killing 100 spores: "But if you're doing it to 10 billion spores," he says, "you're going to have some escapes."
If just a few spores were still alive in each of the samples sent out, Keim says, then they probably aren't dangerous. It takes a lot of anthrax bacteria to make people sick, he says. Nevertheless, he wonders why the Army lab failed to notice that some spores in the samples were still alive. Testing should be routine before shipments.
The CDC has had its own problems with anthrax. Last year, the agency revealed that as many as 75 workers in its labs may have been exposed because the spores were not properly killed.
ROBERT SIEGEL, HOST:
The United States military is looking into why deadly anthrax bacteria were shipped from one of its facilities to civilian labs in nine states and a military base in South Korea. NPR's Geoff Brumfiel has the latest on the case.
GEOFF BRUMFIEL, BYLINE: The anthrax came from a lab at the Army's Dugway Proving Ground in Utah. They were supposed to be dead samples, but late last week, a civilian lab in Maryland that was sent some of the anthrax found it was still alive.
PAUL KEIM: Anthrax is one of the most difficult microorganisms to kill.
BRUMFIEL: Paul Keim studies anthrax at Northern Arizona University. The bacteria hide inside tough spores that can survive for years and still infect people. The Army facilities zapped the anthrax with radiation. Obviously, Keim says, something went wrong. Maybe they didn't do it long enough to kill everything.
KEIM: One of the things that can happen is they set it up and they do it and then they find out later that it only killed 99.99 percent, which is enough if you're only doing it to 100 spores, but if you're doing it to 10 billion spores, you're going to have some escapes.
BRUMFIEL: If just a few spores were alive in each sample sent out then Keim says they probably aren't dangerous. It takes a lot of anthrax bacteria to make people sick. Nevertheless, he wonders why the Army lab failed to notice the samples were still partially alive. It's routine to check before shipping them to other labs.
KEIM: This is high school microbiology. You take these things and you put them on petri dishes and look to see if anything grows.
BRUMFIEL: The Pentagon needs to conduct a thorough investigation, says Tom Inglesby of the University of Pittsburgh Medical Center.
TOM INGLESBY: It's really important to understand whether the safety culture is strong in the institution. Is the training right for the institution? Are people following the protocols that were intended for this kind of work?
BRUMFIEL: Inglesby helped to investigate a similar lapse last year at the Centers for Disease Control and Prevention where dozens of workers may have been exposed to live anthrax. The direct cause was a failure to completely kill the bacteria, but the investigation found a flawed safety culture was also to blame. So far, no one has become sick from this latest incident, but 22 individuals in South Korea are getting the powerful antibiotic CIPRO just to be safe. And here in the U.S., the CDC says another four lab workers are being treated as a precaution. Geoff Brumfiel, NPR News. Transcript provided by NPR, Copyright NPR.