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Gary Evans writes Hospital Infection Control & Prevention (HIC), Hospital Employee Health (HEH) and contributes to IRB Advisor (IRB). As senior writer at AHC, Evans has written numerous articles on infectious disease threats to both patients and health care workers, including pandemic influenza, MERS and Ebola. He has been honored for excellence in analytical reporting five times by the National Press Club in Washington, DC.
The fatalities that resulted after a Centers for Disease Control and Prevention lab scientist rapidly prepared influenza strain isolates last January -- cutting safety protocols short in order to make it to a high-noon agency meeting -- were all … chickens.
This could have been a much different story.
The highly pathogenic H5N1 avian strain that killed the birds – it isn’t dubbed the “chicken Ebola” for nothing -- also has a 60% mortality rate in humans, but it does not transmit very effectively person to person.
The lab samples were prepared in a 52-minute session in a CDC BSL-3 lab. Properly running the full protocol would have taken 1.5 hours, but the lab researcher signed out at 11:45 to make it to the aforementioned meeting, the agency reported in an internal investigation of the mishap. A lab freezer holding samples of both H5N1 and a relatively benign H9N2 avian flu strain was accessed twice during the session, which apparently resulted in viral cross contamination at some point during the procedure.
The contaminated strain was sent to a U.S.D.A. lab in Athens, GA, where scientists took appropriate precautionary measures even though the flu sample they thought they were receiving was the milder H9N2 strain. When inoculated chickens began dying, they took a closer look at the CDC flu isolate, identifying the cross contamination with H5N1.
They alerted the CDC lab, and therein hangs another tale that reflects none too well on the safety culture at the agency. Making matters worse was that the incident was not reported up the chain of command. At a July press conference to talk about a completely separate lab incident involving anthrax, CDC Director Tom Frieden, MD, said he only learned of it days before, though lab officials had apparently been notified months hence. He was not amused.
Though disciplinary action is under consideration, nothing was announced in that regard with the recent release of a CDC report on the incident. “Although several factors contributed to the delay in reporting the incident, the primary factors were 1) a lack of sound professional judgment by those aware of the contamination; and 2) insufficient or ambiguous select agent and institutional reporting requirements,” the CDC reported.
The latter sounds like a reach, as one would think erring on the side of caution and reporting the incident would be the default position if you’re dealing with something as pathogenic as H5N1. The other concern is that the cross contamination could have made this lethal strain -- the original 'bird flu' if you will -- more transmissible between humans, which brings the word pandemic into our hypothetical discussion. Fortunately, we have only an unexpected poultry cull as the end result of this human error, which was compounded by fear of reprisal or plain ignorance in the subsequent failure to report the incident.