Chapter: Biotechnology Applying the Genetic Revolution: Biowarfare and Bioterrorism
The 2001 Anthrax Attack in the United States
THE
2001 ANTHRAX ATTACK IN THE UNITED STATES
Shortly after the terrorist attack on
the World Trade Center in September 2001, anthrax spores were distributed via
the U.S. Postal Service. The anthrax attack was notable in two respects. First,
it killed only a small handful of victims, supporting the contention that biological
warfare is not usually very effective in practice. Second, it generated a
vastly disproportionate reaction, illustrating the importance of the
psychological aspects of bioterrorism. Undoubtedly governmental overreaction
and public panic did far more damage than the anthrax attack itself.
The anthrax attack came from inside the
United States. Furthermore, although the case has not been solved at the time
of writing, it is thought likely that the perpetrator was an insider in
America’s own biological warfare research establishment. The attacker used the
Ames strain of Bacillus anthracis , which is widely used in laboratories
in theUnited States.
A major problem with tracing the origin
of anthrax outbreaks is that all of the strains of Bacillus anthracis are
closely related and difficult to tell apart. No differences in either 16S rRNA
or 23S rRNA sequence occur between different strains. In practice analysis is
done using variable number tandem repeats or VNTRs. For example, the vrrA gene
of Bacillus anthracis contains from two to six copies of the sequence
CAATATCAACAA within the coding region for a protein of unknown function ( Fig.
23.4 ). These repeats were probably originally generated by slippage of DNA polymerase
during replication. The repeats do not alter the reading frame, but result in
corresponding repeats of the four-amino-acid sequence Gln-Tyr-Gln-Gln within
the encoded protein. Several other VNTRs are also now used, including some on
the pOX1 virulence plasmid. The greatest diversity of Bacillus anthracis strains,
as assessed by multiple VNTR analysis, comes from Southern Africa, which is
therefore regarded as theprobable homeland of anthrax.
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