Zoonotic Diseases

Diseases discussed here have a history of use as an agent for biological warfare, either in the U.S. or abroad. Its use may have been experimental or actual, and any detrimental consequences upon humans, animals or the environment may have been intentional or not, depending on the circumstances, the point in time, and the nature of the disease.

Sunday, May 22, 2011


ANTHRAX, HUMAN, 2001 - USA (03): MORE QUESTIONS - An Innocent Man Blamed?
A ProMED-mail post

ProMED-mail is a program of the
International Society for Infectious Diseases

Date: Thu 19 May 2011
Source: McClatchy Newspapers [edited]

Buried in FBI laboratory reports about the anthrax mail attacks that
killed 5 people in 2001 is data suggesting that a chemical may have
been added to try to heighten the powder's potency, a move that some
experts say exceeded the expertise of the presumed killer. The lab
data, contained in more than 9000 pages of files that emerged a year
after the Justice Department closed its inquiry and condemned the late
Army microbiologist Bruce Ivins as the perpetrator, shows unusual
levels of silicon and tin in anthrax powder from 2 of the 5 letters.
Those elements are found in compounds that could be used to weaponize
the anthrax, enabling the lethal spores to float easily so they could
be readily inhaled by the intended victims, scientists say.

The existence of the silicon-tin chemical signature offered
investigators the possibility of tracing purchases of the more than
100 such chemical products available before the attacks, which might
have produced hard evidence against Ivins or led the agency to the
real culprit. But the FBI lab reports released in late February [2011]
give no hint that bureau agents tried to find the buyers of additives
such as tin-catalyzed silicone polymers.

The apparent failure of the FBI to pursue this avenue of
investigation raises the ominous possibility that the killer is still
on the loose.

A McClatchy analysis of the records also shows that other key
scientific questions were left unresolved and conflicting data wasn't
sorted out when the FBI declared Ivins the killer shortly after his
[29 Jul 2008], suicide. One chemist at a national laboratory told
McClatchy that the tin-silicone findings and the contradictory data
should prompt a new round of testing on the anthrax powder. A senior
federal law enforcement official, who was made available only on the
condition of anonymity, said the FBI had ordered exhaustive tests on
the possible sources of silicon in the anthrax and concluded that it
wasn't added. Instead, the lab found that it's common for anthrax
spores to incorporate environmental silicon and oxygen into their
coatings as a "natural phenomenon" that doesn't affect the spores'
behavior, the official said.

To arrive at that position, however, the FBI had to discount its own
bulk testing results showing that silicon composed an extraordinary
10.8 percent of a sample from a mailing to the New York Post and as
much as 1.8 percent of the anthrax from a letter sent to Democratic
Sen. Patrick Leahy of Vermont, far more than the occasional trace
contamination. Tin -- not usually seen in anthrax powder at all -- was
measured at 0.65 percent and 0.2 percent, respectively, in those
letters. An FBI spokesman declined to comment on the presence of tin
or to answer other questions about the silicon-tin connection.

Several scientists and former colleagues of Ivins argue that he was a
career biologist who probably lacked the chemistry knowledge and
skills to concoct a silicon-based additive. "There's no way that an
individual scientist can invent a new way of making anthrax using
silicon and tin," said Stuart Jacobsen, a Texas-based analytical
chemist for an electronics company who's closely studied the FBI lab
results. "It requires an institutional effort to do this, such as at a
military lab." Martin Hugh-Jones, a world-renowned anthrax expert who
teaches veterinary medicine at Louisiana State University, called it
"just bizarre" that the labs found both tin -- which can be toxic to
bacteria such as anthrax during lab culturing -- and silicon. "You
have 2 elements at abnormally high levels," Hugh-Jones said. "That
reduces your probability to a very small number that it's an

The silicon-tin connection wasn't the only lead left open.... In
April [2011], McClatchy reported that after locking in on Ivins in
2007, the bureau stopped searching for a match to a unique genetic
bacterial strain scientists had found in the anthrax that was mailed
to the Post and to NBC News anchor Tom Brokaw, although a senior
bureau official had characterized it as the hottest clue to date. FBI
officials say it's all a moot point, because they're positive they got
the right man in Ivins. A mentally troubled anthrax researcher at the
US Army Medical Research Institute of Infectious Diseases [USAMRIID]
at Fort Detrick, Maryland, Ivins overdosed on drugs not long after
learning that he'd soon face 5 counts of capital murder.

In ending the inquiry last year [2010], the Justice Department said
that a genetic fingerprint had pointed investigators to Ivins' lab,
and gumshoe investigative techniques enabled them to compile
considerable circumstantial evidence that demonstrated his guilt.
Among these proofs, prosecutors cited Ivins' alleged attempt to steer
investigators away from a flask of anthrax in his lab that genetically
matched the mailed powder -- anthrax that had been shared with other
researchers. They also noted his anger over a looming congressional
cut in funds for his research on a new anthrax vaccine. However, the
FBI never found hard evidence that Ivins produced the anthrax or that
he scrawled threatening letters seemingly meant to resemble those of
Islamic terrorists. Or that he secretly took late-night drives to
Princeton, New Jersey, to mail them. The FBI declared Ivins the killer
soon after paying USD 5.8 million to settle a suit filed by another
former USAMRIID researcher, Steven Hatfill, whom the agency mistakenly
had targeted earlier in its investigation.

The letters, mailed just weeks after the [11 Sep 2001] terrorist
attacks, not only went to the New York Post, Leahy, and Brokaw, but
also to American Media Inc. in Boca Raton, Florida, and to Democratic
then-Sen Tom Daschle of South Dakota. 5 people died, 17 were sickened,
and about 31 000 were forced to take powerful antibiotics for weeks.
Crews wearing moon suits spent several weeks eradicating the spores
from a Senate office building and a central Postal Service facility in

The FBI guarded its laboratory's finding of 10.8 percent silicon in
the Post letter for years. New York Democratic Rep. Jerrold Nadler
asked FBI Director Robert Mueller how much silicon was in the Post and
Leahy letters at a hearing before the House Judiciary Committee in
September 2008. The Justice Department responded 7 months later that
silicon made up 1.4 percent of the Leahy powder (without disclosing
the 1.8 percent reading) and that "a reliable quantitative measurement
was not possible" for the Post letter. The bureau's conclusions that
silicon was absorbed naturally drew a gentle challenge in February
from a panel of the National Academy of Sciences, which evaluated the
investigation's lab work.

While finding no evidence that silicon had been added to the mailed
anthrax, the panel noted deep in its report that the FBI had provided
"no compelling explanation" for conflicts in silicon test results
between the Sandia National Laboratories and its own lab. Sandia --
which used electron microscopes, unlike the FBI -- reported only 1/10
as much silicon in the New York Post letter as the bureau's lab did.
Sandia said it was all embedded in the spore coatings, where it wasn't
harmful. The Armed Forces Institute of Pathology ran a 3rd set of
tests and found pockets of heavy silica concentrations, but it
couldn't say whether they were inside or outside the spores.

Jacobsen, the Texas chemist, suspects that the silica pockets
represented excess material that went through a chemical reaction and
hardened before it could penetrate the spores.

The National Academy of Sciences panel wrote that the varying
composition of the powder might have accounted for the differing
findings. While finding no evidence that silicon was added, the panel
said it "cannot rule out the intentional addition of a silicon-based
substance ... in a failed attempt to enhance dispersion" of the New
York Post powder. Tufts University chemistry professor David Walt, who
led the panel's analysis of the silicon issue, said in a phone
interview that "there was not enough silicon in the spores that could
account for the total silicon content of the bulk analysis." He said
it was unclear whether the "trace" levels of tin were significant.

During the FBI's 7-year hunt, the Department of Homeland Security
commissioned a team of chemists at the Lawrence Livermore National
Laboratory in California to grow anthrax-like spores under varying
conditions to see how much silicon would end up naturally in the final
product. They found little, if any, silicon in most cases, far less
than was in the New York Post letter, said Stephan Velsko, one of the
2 researchers. He called the tin readings from the FBI's anthrax data
"baffling." Peter Weber, Velsko's co-researcher, said the academy
panel's focus on the conflicting data "raises a big question," and
"it'd be really helpful for closure of this case if that was
resolved." He suggested that further "micro-analysis" with a highly
sophisticated electron microscope could "pop the question marks really
quickly." In a chapter in a recently updated book, "Microbial
Forensics," Velsko wrote that the anthrax "must have indeed been
produced under an unusual set of conditions" to create such high
silicon counts. That scenario, he cautioned, might not be "consistent
with the prosecution narrative in this case."

About 100 tin-catalyzed silicone products are on the market, and an
even wider array was available in 2000 and 2001, before the mailings,
said Richie Ashburn, a vice president of one manufacturer, Silicones
Inc., in High Point, North Carolina. Mike Wilson, a chemist for
another silicone products maker, SiVance, in Gainesville, Florida,
said that numerous silicon products could be used to make spores or
other particles water-repellent. He also said that the ratios of
silicon to tin found in the Post and Leahy samples would be "about
right" if a tin-catalyzed silicone had been added to the spores.

Jacobsen, a Scottish-born and -educated chemist who once experimented
with silicon coatings on dust particles, said he got interested in the
spore chemistry after hearing rumors in late 2001 that a US military
facility had made the killer potions. He called it "outrageous" that
the scientific issues haven't been addressed. "America, the most
advanced country in the world, and the FBI have every resource
available to them," he said. "And yet they have no compelling
explanation for not properly analyzing the biggest forensic clue in
the most important investigation the FBI labs had ever gotten in their

As a result of Ivins' death and the unanswered scientific issues,
Congress' investigative arm, the Government Accountability Office, is
investigating the FBI's handling of the anthrax inquiry.

[Byline: Greg Gordon, Tish Wells contributed]

Communicated by:

[This report is parallel to the evidence we -- Barbara Rosenberg,
Stuart Jacobsen, and myself -- submitted to the NAS (National Academy
of Sciences) committee last summer (2010). A fuller version is in the
final stages of preparation for submission to a suitable journal. The
sad part about this is that Sandia provided the FBI with key evidence
on the levels of silicone in letter-content spores in late October
2001. If the latter had had the wit to follow up on it at that time
all this would be history and the true perpetrator(s) suitably dealt
with. Also tracking past sales of silane and siloxane chemicals to
institutes and agencies handling _Bacillus anthracis_ would have
produced a short list for immediate visits and interviews by FBI
agents with search warrants, and then the names of who would have had
access to the products of their polymerization research. - Mod.MHJ]

[see also:
Anthrax, human, 2001 - USA (02): ongoing questions 20110223.0601
Anthrax, human, 2001 - USA: Nat'l Research Council rep.
Anthrax, human, 2001 - USA (06) 20100921.3407
Anthrax, human, 2001 - USA (05) 20100424.1326
Anthrax, human, 2001 - USA (04) 20100324.0933
Anthrax, human, 2001 - USA (03) 20100305.0727
Anthrax, human, 2001 - USA (02): FBI case closed 20100219.0575
Anthrax, human, 2001 - USA 20100125.0281
Anthrax, human, 2001 - USA (03): NAS review 20090507.1707]
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