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This award-winning blog supplements the articles in Hospital Infection Control & Prevention.

CDC anthrax investigation: No infections, no environmental contamination, but first head may roll

The director of a bioterror lab implicated in the possible anthrax exposures to other lab workers at the Centers for Disease Control and Prevention has been “reassigned” pending results of the ongoing investigation, according to a news report that cited anonymous sources.

At the same time, another news report indicated that an initial round of environmental testing has not detected any anthrax in the lab areas where exposures were feared to have occurred, though the labs remain closed as the investigation continues.

Thus it appears at this juncture that we have a breach in biosafety protocol or policy that is more likely to result in job termination than human infection. So far, 84 CDC employees have been offered prophylaxis for anthrax, though as word of the lack of environmental contamination circulates, more of them may turn it down. Still, if told you may been exposed to “Ames” anthrax -- the strain proven to be lethal in the 2001 anthrax letters that evidence suggests were mailed out by a literal mad scientist -- would you turn down an offer of the standard post-exposure prophylaxis of a 60-day regimen with ciprofloxacin or doxycycline? Two of the first 54 CDC employees offered the drugs did. Moreover, 19 declined the anthrax vaccine, which is more understandable given its controversial history.

If you will pardon the ghoulish side note, this 60-day incubation period apparently applies to exposures to living humans. Anthrax in its virtually impervious spore form, having killed either animal or man, can sleep much longer in the grave and still arise another day. Cremation is recommended.

The post-exposure prophylaxis was recommended because the CDC employees were working in lower level labs with what was presumed to be inactivated anthrax incapable of causing infections. But the initial CDC reports found that the anthrax had survived, as the attempt to kill the bug with chemicals was insufficient. This was discovered after a few days of experiments had already been conducted in the other labs, where workers were like so many unprotected electricians wiring circuits and switches after being assured that the main power was off.

The problem the bioterror lab researchers were trying to solve is indeed a vexing one, how to tell real anthrax from a wide variety of hoax powders that have caused chaos and fear since the 2001 attacks. If the substance is suspected to be anthrax, labs have to typically subject it to some kind of sterilization killing procedure before conducting confirmatory tests. The CDC was trying to neuter the virulent Ames strain via chemicals rather than radiation, which has proven to do the job but requires equipment not typically available to state and local public health labs. In any case, the tempting speculation is that the corner was cut during the chemical experiment, as the report of dead anthrax turned out to be greatly exaggerated.

The fear that the deadly bacteria may have become aerosolized arose in part because the anthrax was distributed in sealed tubes that were then agitated, much like CDC Director Tom Freiden, MD, must have been when he got the phone call on this one. The former health director of New York City, Freiden no doubt recalls that his predecessor as CDC director, Julie Gerberding, MD, took the helm after emerging as a voice of calm and reason in the near-panic that surrounded the 2001 anthrax attacks. The attacks resulted in harsh criticism that the public health response was confusing and inconsistent. Bruce Edwards Ivins, a government biodefense researcher, had become the leading suspect in a relentless federal investigation into the attacks when he died of apparent suicide via Tylenol PM overdose in 2008.