Entomologist: Insects Could Be Used as Bioweapons

Sonny Ramaswamy is trying to walk a very fine line. He doesn't want to be seen as an alarmist, but he thinks people ought to know about the thought that keeps haunting him these days.

Ramaswamy, who chairs the department of entomology at Kansas State University, is concerned that the tiny little insects he has spent a lifetime studying could become implements of international terrorism.

It's possible, he says, that even a stable fly, or something as tiny as an aphid, could be used to distribute deadly pathogens over a wide geographical area in a surprisingly rapid and efficient manner. Bugs as delivery systems for weapons of mass terror.

"It wouldn't be as spectacular as the World Trade Center," he says, "but it would be more insidious."

Poison-Fed Flies

His concern began almost as a joke with a colleague at Kansas State. The two entomologists were talking a couple of years ago about the war in Afghanistan and the effort to flush terrorists out of the Tora Bora caves with high pressure bombs.

"They weren't having much success," Ramaswamy says, recalling the discussion with his colleague, an expert on flies that bite, particularly stable flies that can make life miserable for livestock.

Stable flies zero in on body heat and exhaled carbon dioxide, and they are accustomed to feeding on bacteria, some of which can be deadly. So as the two men chatted, Ramaswamy suggested that stable flies could be fed anthrax, and then released into the caves.

"Let the flies go in and bite those suckers," he says. The flies rid themselves of the anthrax by either vomiting or defecating, and the wound from the bite causes itching, so the natural inclination is to scratch the bite, thus rubbing the anthrax into the skin, he adds.

"It's a weird thought," he says. "We kind of laughed about it, and then forgot about it."

But a short time later Ramaswamy was at a meeting of the Entomological Society of America and the question arose about how to deal with the spread of pathogens in this country by insects that arrived accidentally, or were deliberately introduced by terrorists bent on more sophisticated means of creating havoc than blowing themselves up.

He returned to the campus in Manhattan, Kan., and discussed the issue with some of his colleagues, including entomologist John Reese, an aphid expert, and geographer Shawn Hutchinson, a mapping expert. Their target: a particularly insidious critter known as the Asian soybean aphid (Aphis glycines), a flying aphid that had spread at an astounding rate since it was first discovered in this country just four years ago.

No one is suggesting that this beast was introduced on purpose, or has anything to do with international terrorism, but it offered the researchers an opportunity to study how a small insect expands its territory, and whether the direction of future expansion could be predicted.

Having said that, however, Ramaswamy is quick to admit that this little insect might be ideally suited for terrorist activities.

Aphids Gone Berserk

It can reproduce without sex, so it only takes one female to start a colony that can grow at alarming rates. And unlike the aphids that devour rose bushes, this one can fly, thus making mobility much easier.

Prior to 2000, this aphid lived only in Asia, but after it arrived on this continent it spread from the Dakotas to Virginia, across 11 states, in less than four years, and it has been blamed for crop losses of more than $2.2 billion.

Sometimes, the aphids moved in swarms as they ate their way across a large slice of America's heartland. They achieved notoriety in Toronto when they appeared in such a dense swarm that the Blue Jays had to cancel a baseball game because of low visibility, Reese says.

"No aphid has ever built up to numbers quite like that," Reese says.

And it did it in a remarkably short period of time.

Meanwhile, Hutchinson set out to map the spread of the critter using a powerful technique known as a "geographical information system," or GIS, which combines visuals and data to document conditions across a landscape. He had some pretty basic questions to answer. How was the aphid expanding its territory so rapidly? How did it get from one point to the next? It could fly, but not hundreds of miles. Was it borne on the wind? Did it hitch rides?

One early conclusion was that the aphid was moving more in an east-west direction. So students at the university were recruited as sentinels to monitor the aphid's movement from Missouri, where it had already established a stronghold, into Kansas, where it had not been found.

"We had people running up and down the border" between the two states, hoping to catch it in the act, Ramaswamy says. But they didn't. And then last August, the Asian soybean aphid showed up in Manhattan, in the university's own back yard, at least a two-hour drive from the border.

How did it get there without being detected crossing the border? Rasmaswamy has a theory.

Hitchhiking Bugs

In a hobby that only an entomologist can appreciate, Rasmaswamy pays attention whenever he sees an insect land on his car.

"I will speed up to 90 miles per hour, or hit the brakes, or whatever," to see if he can shake or blow the critter off, he says. "But the bug is not going to be dislodged. It's hanging on for dear life."

So he theorizes that a female aphid hopped on somebody's car, possibly while they were stopped for gasoline in Missouri, and held on until the next stop, which turned out to be near Manhattan. Then it jumped off and headed for the lush soybean fields.

All it would take, he says, would be a single female, which would begin feeding and reproducing, to start a new colony in a process that likely would be repeated over and over again, wherever soybeans grow, or wherever conditions are suitable for this heavy eater to multiply.

As so many insects do, it could carry all kinds of pathogens, but even just doing what comes naturally, it could cause economic ruin over a wide area.

Of course, as biological warfare experts are quick to point out, bugs may not be the best way to distribute pathogens. A bug doesn't always go where you want it to go, one expert told me.

But if someone doesn't really care who dies in a given geographical area, even if the bug ends up biting the hand that feeds it, it might be useful. At the very least, it's worth honing our skills to track, and if possible, control the movement of insects across our land.

Just because that's not the kind of spectacular event that appeals to terrorists today, that doesn't mean it won't be in the future.

Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.

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