Color-enhanced scanning electron micrograph shows splenic tissue from a monkey with inhalational anthrax; featured are rod-shaped bacilli (yellow) and an erythrocyte (red)
Credit: Arthur Friedlander
A university professor has allegedly mailed anthrax to the Pakistani prime minister’s office in October, accoding to today’s The New York Times. Could this be the beginning of a new anthrax scare? Is history repeating itself?
If true, any individual considering such “attacks” can no longer assume that their weapons are untraceable, as shown by the anthrax scare in 2001.
Below is an excerpt from an article I published in The Human Rights Quarterly:
A week after the 9/11 terrorist attacks, lawmakers on Capitol Hill and media outlets in Florida and New York began to receive mysterious mail laden with anthrax spores. Within two months, five people were dead and seventeen others were sickened from contact with anthrax powder, among them several US postal workers. Anthrax is an infection caused by Bacillus anthracis, a gram-positive, spore-forming bacterium with a high level of genetic uniformity among its dozens of different strains. A few years earlier, Paul Keim, a microbial geneticist at Northern Arizona University, and his colleagues identified thirty-one unique DNA sequences referred to as amplified fragment length polymorphism (AFLP) markers among various anthrax strains.
AFLP can be used as a powerful DNA fingerprinting technique. It uses polymerase chain reaction (PCR) to selectively amplify fragments of genomic DNA of any origin. The AFLP technique allows a large number of DNA fragments to be amplified and detected without requiring knowledge of the sequence of the DNA. Applying this technique to a sample of the anthrax isolated from the body of one of the victims, Dr. Keim identified the attack strain as Sterne-Ames– the most virulent of all anthrax strains. Although different grades of anthrax were used in the attacks, all of them were of the Ames strain.
Under the coordination of the FBI, the then-director of The Institute for Genomics Research (TIGR), Claire Fraser-Liggert, led a team to decode the genome of anthrax DNA (approximately five million base pairs). TIGR set out to establish a genealogy of the anthrax cultures, beginning with the Ames ancestor that was isolated from a cow, which succumbed to the disease in Texas in 1981. It turned out that the DNA of the strain used in the terrorist attack was virtually identical to the Ames ancestor–it seemed to be indistinguishable from any of the thousands of known anthrax cultures. Indeed, strains of Bacillus anthracis are available commercially.
The New York Times reported in 2008 that an army microbiologist from Fort Detrick, Maryland found a way to distinguish the anthrax cultures by spreading the spores from the anthrax used in the attacks on growth media. The spores grew into various subpopulations, including one with a distinct morphology. This “morph” had a major genetic change referred to as an indel (insertion or deletion of DNA), which gave the strain used in the attack a unique genetic marker.
Over the next two years, seven more such “morphs” were identified and their DNA sequenced. The anthrax spores collected from all of the attack mailings contained four identical “morphs”. Under subpoena of the FBI, 1,070 anthrax samples were collected from laboratories in the US and around the world. Eight of these samples were found to have the same four “morphs” as the strain used in the attacks.
The source of the eight samples was soon revealed: a master flask of Sterne-Ames anthrax strain referred to as RMR-1029 that was under the custody of Dr. Bruce Ivins, a researcher at the US Army Medical Institute of Infectious Diseases at Fort Detrick. Ivins committed suicide in July 2008, just one month before the FBI made announced the solving of the seven-year-long anthrax puzzle. Such microbial forensics tools can be applied to future biological threats–individuals contemplating such “attacks” can no longer assume that their weapons are untraceable.