Saturday, March 18, 2006

The specter for biowarfare seemingly gets scarier all the time.
Into a relatively innocuous bacterium responsible for a low-mortality pneumonia, Legionella pneumophila, Popov and his researchers spliced mammalian DNA that expressed fragments of myelin protein, the electrically insulating fatty layer that sheathes our neurons. In test animals, the pneumonia infection came and went, but the myelin fragments borne by the recombinant Legionella goaded the animals' immune systems to read their own natural myelin as pathogenic and to attack it. Brain damage, paralysis, and nearly 100 percent mortality resulted: Popov had created a biological weapon that in effect triggered rapid multiple sclerosis. (Popov's claims can be corroborated: in recent years, scientists researching treatments for MS have employed similar methods on test animals with similar results.)
Wisely, Technology Review got Allison Macfarlane to make the case for not getting too excited about the about their above article.
For example, data on the infectiousness of an agent varies widely, depending on the agent. Because of limited experience with anthrax, susceptibility data have often been extrapolated from animal trials that have little bearing on human response to agents. In the case of smallpox, with which scientists had much experience in the 20th century, some factors remain uncertain, such as the transmission rate.

In the models of bioweapons attacks, the ability to weaponize an agent and disperse it effectively is estimated in part from open-air trials done by the U.S. Army between the 1940s and 1960s. These trials used live simulants of agents on major U.S. cities, but the behavior of a real bioweapon agent in such a situation remains uncertain. Williams's article doesn't describe in any detail the ability of terrorists to weaponize any of the theorized agents. Yet making effective bioweapons would take a tremendous amount of work.

While a state-sponsored program might have the means to do that work, terrorist groups probably don't. With so much uncertainty surrounding the outcome of a bioweapons attack, it does not make sense to plan extensive biodefense programs when more-certain threats, particularly those involving nuclear weapons, require attention.
Macfarlane is right about these uncertainties, but I can't fully endorse his conclusion. In the long term (I'd guess thirty years tops), biotechnology and nanotechnology will solve the weaponization "problem." The economic motivation for this advance is clear: farmers have been fighting a biowar against pests for a long time. They will gladly pay for better weapons. We can't wait until then to start researching countermeasures against the use of these weapons on humans.

We can already easily engineer diseases capable of defeating the individual human immune system. It still probably takes a lot of infrastructure to overwhelm the collective immune system of the human species (i.e., a lot of us survive), but that won't be true forever. The collective natural immune systems of the developed nations will ultimately be augmented by artificial ones. (The undeveloped nations will not probably not survive the next century without a lot of help.) Alas, grand artificial immune systems are very much public goods, and politicians are usually myopic or backward-looking. I predict artificial immune systems will be underfunded until a catastrophe makes their necessity manifest.


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