A theory that won't fly
Ebola and other deadly viruses have been much in the news lately, and much in people's minds. Not just for what they aredeadly at close rangebut for what, with sinful human intervention, they might be: rampant, random, long-distance killers, borne on the winds.
Popular culture has a recurrent fascination with doomsday pathogens. Michael Crichton's The Andromeda Strain was a classic incarnation of this scary scenario. The recent sci-fi film "Species" is its latest iteration, although this time the evil incarnate has shed its viral coating: It is naked DNA sent from outer space and embodied in an alien-supermodel hybrid. In Richard Preston's book The Hot Zone and the film "Outbreak," we're frightened by real viruses, specifically Ebola. In the film, a new mutant strain, carried by a monkey, will depopulate California unless Dustin Hoffman can save the day, and he has only an hour or so to do it.
The ostensibly responsible media are not immune to the temptation to stir these fears. In a May 12 editorial, the New York Times declared: "A modest genetic change might enable Ebola to spread rapidly through the air..."
That very same day, in the news section, Times reporter Lawrence K. Altman, M.D., handled the matter more soberly. Reporting from the Centers for Disease Control and Prevention in Atlanta, he wrote, "The deadly Ebola virus continues to spread in Zaire, chiefly affecting health care workers... [It] apparently spread initially among [doctors] and nurses who operated on a patient in Kikwit." Dr. Altman, an infectious-disease specialist who once worked at the CDC, added, "Transmission presumably was through contaminated blood..."
Can a bloodborne or body fluid-borne virus be transformed by a single mutation into an airborne agent (a "flyer"), as the scare scenarios imply? It's conceivable. But it's "probably unlikely," according to virologist Beth Levine, M.D., director of virology research in the infectious diseases division at Columbia University's College of Physicians and Surgeons. "Single amino acid mutations can change the tropism [the residential preference] of a virus" in some experimental situations, Dr. Levine says, "but there haven't been any examples of such mutations actually occurring in nature, changing a virus from a bloodborne or bodily fluid route of transmission to a respiratory route."
So, says Dr. Levine, "The media's claim is not totally without scientific basis. But there are no precedents for it, and it's unlikely.
"I think it's irresponsible to raise that concern," she added, "because in general viruses are very well-adapted to their milieuand they don't just suddenly change their environment." Will this kind of level-headed assessment quell media hysteria? Stay tuned.
David R. Zimmerman
DAVID R. ZIMMERMAN, adjunct professor at the Columbia Graduate School of Journalism, is the editor of Probe, a newsletter of science and media criticism. He has taught at the New School for Social Research.