This week, it was reported that a Department of Defense (DoD) facility has inadvertently shipped samples of live Bacillus anthracis, the causative agent of the disease anthrax. Subsequent updates have indicated that up to 18 domestic laboratories may have received the improperly inactivated samples, intended for use during diagnostic development, from a period between March 2014 and April 2015. Additionally, a sample was sent to Osan Air Base in South Korea, where 22 individuals were apparently exposed during an exercise. An effort to confirm additional at risk receiving facilities and personnel is currently being undertaken, and CDC has been alerted and is conducting an investigation.
This episode comes nearly a year after two separate biosafety lapses at the CDC. In the first, an improperly inactivated sample of B. anthracis was removed from a high containment laboratory, exposing 67 individuals. In the second, CDC scientists sent a sample of low pathogenic avian influenza H9N2 to a USDA laboratory. This would have been fine, except that it was subsequently discovered that the sample was contaminated with highly pathogenic avian influenza H5N1. See this Science article for good recap of both lapses. This latest incident appears to couple problems with ineffective inactivation with the transport of select agents.
It’s important to note that no infections have been reported as a result of these miscues, and the risk to public health is deemed to be very low at this time. Fortunately, anthrax does not spread by person to person transmission. If a more transmissible pathogen had been involved, the risk to public health would have been increased. A total of 26 individuals have started courses of post-exposure prophylaxis, including all 22 individuals exposed in South Korea. The Center’s Dr. Amesh Adalja has explained why he believes there will not be any infections resulting from this lapse at Tracking Zebra.
Another important point to keep in mind is that, while B. anthracis is a Category A bioterror agent, and regulated under the Federal government’s Biological Select Agent and Toxins program, we have no indication that the agent that was shipped was in any way weaponized. In both cases involving B. anthracis, scientists were engaged in biodefense research. The United States does not operate an offensive biological weapons program, and has not since the Nixon administration. The same cannot be said for every nation on earth. You may well have noticed that a South Korean facility was included in the list of receiving facilities, and might wonder why that might be. The threat posed to our South Korean allies by a suspected North Korean biological weapons program is the most likely explanation.
How could this happen? Before considering systems and scientists, let’s think about the agent in question. In the past, B. anthracis has been considered a candidate for weaponization in part because of its toughness. This ability to persist is due to the spore that covers the exterior of the bacterium, and allows it to survive for long periods in conditions that would have killed other microbes.
That said, a review of the inactivation technology and associated protocols used to render the bacteria inactive at the facility in question is clearly needed. The other alternative is that there was some degree of operator error. While we wait for the facts to emerge, we can be thankful that no one has become ill or died due to these events. Prompt corrective action is needed to ensure that this vital research is conducted in a safe and secure manner.