Monday, July 14, 2014

CDC scientists' lack of understanding of anthrax is shocking and terrifying

The WaPo has published the full text of the CDC report on its anthrax mishap last month, with mention of a number of other, almost identical even from the same lab... in which highly virulent, live bacteria, including anthrax, H5N1 avian flu and Clostridium botulinum were transferred to other labs, on the assumption they were benign strains or had been killed.

However, the report deemphasizes a critical safety breech:  that multiple lab personnel failed to appreciate the differences between anthrax spores and vegetative organisms.  It further minimizes the risk from live spores.

The report repeatedly states that the procedure used to inactivate anthrax would have worked for vegetative forms of anthrax.  The report admits the procedure did not completely kill spores.

There's an understatement.  Vegetative, growing anthrax bacteria can be killed by almost anything, including flying through the air. They cannot be used as a weapon due to their fragility.  

But spores are an entirely different matter.  There are very few things that kill anthrax spores, which can live for hundreds of years. That is why it was so difficult and expensive to decontaminate buildings contaminated with them.  An area harboring anthrax spores remains dangerous for the foreseeable future.  Scotland's Gruinard Island, where anthrax was tested during World War 2, was off limits to humans for 45 years, until it was decontaminated by being bathed in formaldehyde.

At CDC, an inactivation procedure was used on anthrax spores that was developed for vegetative, growing Brucella bacteria, yet was expected to inactivate spores.  This fact alone is astounding.  It shows complete lack of understanding of what the scientists were dealing with.  The report says its scientists had "inadequate knowledge of the peer-reviewed literature" on anthrax.  I would say they knew nothing about how to work with anthrax and are lucky they are still alive. They did not understand what they were doing, and should be reassigned away from select agents.

Even after 24 hours in a chemical bath, not all spores were killed.  Four colonies grew from an estimated 50,000 put on a plate.  Based on this, CDC's report claims there was no problem, as not enough spores (only about 1 in 10,000) might have lived to cause trouble.

However, only an estimated 50,000 spores were plated.  But how many were transferred to other labs? That number is never provided.  Bruce Ivins kept 1 trillion spores per ml (milliliter) in his flask at Fort Detrick. Fermenters produce one billion organisms per ml.  Most experiments require many orders of magnitude more than were plated. A reasonable guess might be that 10 billion spores were transferred.  At the given rate of inactivation, a million anthrax spores would have remained viable. According to the NY Times:
Over the next few days, scientists in two other labs where breathing equipment was not used agitated the bacteria and sprayed them with compressed gas, which could have blown spores into the air.
Could have blown spores into the air?  Clearly, these procedures did release spores into the air. Luckily for the scientists, it usually takes thousands of spores to cause infection.  But the occasional person (consider nonagenarian Ottilie Lundgren in Connecticut) may succumb to just a few spores.

The litany of mistakes that were made, detailed in the report's Findings, is breathtaking.  Lack of understanding of anthrax. Lack of SOPs. Lack of appropriate experimental design. Failure to follow CDC's own protocols, where they existed. Lack of supervision. Lack of timely communication when the incident was discovered, including identifying employees who may have been exposed so they could receive prophylaxis. (See page 16 of the Report.)  However, I disagree that it was highly unlikely that staff were exposed to anthrax:  they were, more likely, simply not exposed to enough anthrax spores, along with receiving prophylactic antibiotics, to induce disease.

Good recommendations are made to prevent a repeat in this report.  However, as the NY Times notes below, CDC has failed repeatedly to correct the very same problems identified in the report.  Decades ago, Fort Detrick lost two employees at its research facility to anthrax.  Many of us think it simply isn't possible for thousands of labs to perform this type of work safely.  It needs a tremendous degree of attention, care, and a paranoid mindset.  I would not trust myself to do it.  

It is slow working in a moon suit with a self-contained breathing apparatus.  You don't get to do blockbuster science this way. 

Have lower caliber scientists been shunted to the labs that perform this type of work, when what is required are the highest caliber, in order to do it safely?

UPDATE:  USDA's investigation of CDC finds even more bloopers and blunders, including failure to secure one of the labs that received the live anthrax.  People continued to transit the area for days after the mistake was discovered.  The CDC clinic failed to see exposed workers for up to 5 days, and advised some to check themselves for anthrax.  Anthrax was kept in an unlocked hall fridge; elsewhere, anthrax had gone missing.

2nd UPDATE:  Congressional memo with comments on USDA's APHIS report

Congress will be investigating with a hearing July 16.  From the Times:

Several experts on biosecurity noted that the inspector general’s office of the Department of Health and Human Services sent official complaints to the C.D.C. in 2008, 2009 and 2010 about undertrained lab personnel and improperly secured shipments.
Both Dr. Frieden and his predecessor, Dr. Julie L. Gerberding, replied in letters over their signatures that the problems would be fixed.

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