Page:Amerithrax Investigative Summary.pdf/18

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3. Early scientific findings and conclusions

These tests and techniques allowed scientists to make several physical findings regarding the Bacillus anthracis spores used in the letter attacks. The spore particles had a mass median diameter between 22 and 38 microns. They exhibited an electrostatic charge, showed no signs of genetic engineering, and were non-hemolytic, gamma-phage susceptible, antibiotic and vaccine sensitive, and devoid of aerosolizing enhancers (e.g., fumed silica, bentonite, or other inert material). These characteristics were and are inconsistent with weapons-grade anthracis produced by offensive, state-sponsored biological weapons programs.^[1]

Spore powder concentrations ranged from 4.60 x 10¹⁰ to 2.10 x 10¹² colony-forming units per gram, an extraordinarily high concentration. In addition, the spores in the Washington, D.C. letters were of exceptional purity. Spores of such high concentration and purity indicate that they were derived from high quality spore preparations. Spores of this quality are often used in bio-defense research, including vaccine development. It is important to have highly concentrated spores to challenge most effectively the vaccine being tested. Similarly, highly purified spores are necessary to prevent obstruction of the machinery used in those experiments.^[2] These findings meant that the anthrax mailer must have possessed significant technical skill.

↑ Throughout the course of the investigation, repeated challenges have been raised to this finding that the spores were not weaponized. The challenges have their root in an initial finding by the Armed Forces Institute of Pathology (“AFIP”) that, upon gross examination, the spores exhibited a silicon and oxygen signal. However, subsequent analysis of the spores by Sandia National Laboratories, using a more sensitive technology called transmission electron microscopy (“TEM”) – which enabled material characterization experts to focus its probe of the spores to the nanometer scale – determined that the silica was localized to the spore coat within the exosporium, an area inside the spore. In other words, it was incorporated into the cell as a natural part of the cell formation process. “The spores we examined lacked that fuzzy outer coating that would indicate they’d been weaponized,” stated Dr. Paul Kotula of Sandia, who personally examined the spores from the 2001 attacks. When presented with these results, Dr. Peter Jahrling, a USAMRIID scientist who had reviewed the initial AFIP results and stated publicly in late 2001 that the spores had been weaponized, retracted his earlier statement, telling the Los Angeles Times on September 16, 2008, “I believe I made an honest mistake.”
↑ In an aerosol challenge to a particular vaccine, spores in liquid suspension are placed into a nebulizer, also known as a collision, which is used to generate aerosolized particles of the challenge-agent, such as Bacillus anthracis. Once the air flows from the nebulizer through the aerosol chamber, it is recaptured in an all-glass impinger (“AGI”). The AGI is used to force the submersion of the air flow through water, for the effective impingement of the particles into solution. Excessive cellular debris or remnants of growth media in less-pure spore preparations could clog these mechanisms and inhibit the effectiveness of the vaccine challenge.

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[1] Throughout the course of the investigation, repeated challenges have been raised to this finding that the spores were not weaponized. The challenges have their root in an initial finding by the Armed Forces Institute of Pathology (“AFIP”) that, upon gross examination, the spores exhibited a silicon and oxygen signal. However, subsequent analysis of the spores by Sandia National Laboratories, using a more sensitive technology called transmission electron microscopy (“TEM”) – which enabled material characterization experts to focus its probe of the spores to the nanometer scale – determined that the silica was localized to the spore coat within the exosporium, an area inside the spore. In other words, it was incorporated into the cell as a natural part of the cell formation process. “The spores we examined lacked that fuzzy outer coating that would indicate they’d been weaponized,” stated Dr. Paul Kotula of Sandia, who personally examined the spores from the 2001 attacks. When presented with these results, Dr. Peter Jahrling, a USAMRIID scientist who had reviewed the initial AFIP results and stated publicly in late 2001 that the spores had been weaponized, retracted his earlier statement, telling the Los Angeles Times on September 16, 2008, “I believe I made an honest mistake.”

[2] In an aerosol challenge to a particular vaccine, spores in liquid suspension are placed into a nebulizer, also known as a collision, which is used to generate aerosolized particles of the challenge-agent, such as Bacillus anthracis. Once the air flows from the nebulizer through the aerosol chamber, it is recaptured in an all-glass impinger (“AGI”). The AGI is used to force the submersion of the air flow through water, for the effective impingement of the particles into solution. Excessive cellular debris or remnants of growth media in less-pure spore preparations could clog these mechanisms and inhibit the effectiveness of the vaccine challenge.

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