FEATURE ARTICLE
The Growing Threat of Biological Weapons
The terrorist threat is very real, and it's about to get worse. Scientists should concern themselves before it's too late
Steven Block
"Black Biology"
Beyond the smallpox scenario, what has people worried is the impact
of modern biotechnology. For better or worse, the world is in the
midst of a stunning revolution in the life sciences. Scientists have
already determined the complete genomic sequences for more than 30
microbes and even more viruses. The DNA code for the cholera
pathogen (Vibrio cholerae) was recently published, and the
genomes of more than 100 other microorganisms are now being
sequenced??including the bacteria that cause anthrax, plague,
dysentery and typhoid. Of course, the new information is critical
for answering fundamental and practical questions in biology and
medicine, and will be put to direct, practical use in a myriad of
health-related applications. But what about "black
biology"? Could biotechnology be used to produce a new
generation of biowarfare agents with unprecedented power to destroy?
Or is this just alarmist hype? No one can say for sure, but many
molecular biologists familiar with the relevant technologies seem
inclined to a pessimistic view.
A key reason for pessimism is the ease with which genetic
manipulations are now accomplished. Back in the summer of 1997,
JASON (a group of primarily academic scientists, which consults on
technical matters for the U.S. government and its agencies)
addressed the problem of next-generation bioweapons threats. The
JASON study explored a wide range of future possibilities open to
genetically engineered pathogens, including some that could be
achieved with the current state of the art and others that
are??happily??still some way off. The prospects are sobering. Both
bacteria and viruses may now be engineered to be qualitatively
different from conventional bioweapon agents. In terms of
bioweaponry, this includes imbuing them with such
"desirable" attributes as safer handling, increased
virulence, improved ability to target the host, greater difficulty
of detection and easier distribution.
Several broad classes of unconventional pathogens were identified by
JASON. These include "binary" bioweapons, which, by
analogy with chemical weapons, are two-component systems in which
each part is relatively safe to handle, but which become deadly in
combination, and "designer" variations on genes, viruses
and complete life forms, including chimeras that mingle existing
components. Once gene therapy becomes a medical reality, the
technology that allows the repair or replacement of defective genes
might be subverted to introduce pathogenic sequences.
"Stealth" viruses could be fashioned to infect the host
but remain silent, until activated by a trigger. New zoonotic agents
(those transmissible from animals to people) might be developed
specifically for bioweapon purposes by modifying existing pathogens
to seek human hosts. Finally, detailed knowledge of biochemical
signaling pathways could conceivably be used to create
"designer diseases."
Of course, some of these exotic possibilities seem downright
superfluous given the dangers posed by the current generation of
bioweapon agents. Then again, fusion-based hydrogen bombs seem
superfluous, given the destructive power of fission-based weapons.
For now, even the most rudimentary genetic manipulations could be
used to enhance a bioweapons threat, for example by introducing
antibiotic resistance into a weaponized bacterial strain.
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