Six-legged soldiers

Adapted from the epilogue of Six-Legged Soldiers: Using Insects as Weapons of War:

Dusk descends on a sweltering New Orleans. A naked man lies moaning in an apartment a few blocks from Canal Street. His jaundiced body is mottled with bruises where vessels have hemorrhaged. The pillow and bedside are caked with blood that he has vomited. The man's breathing is labored as he drowns in his own fluids.

The window of the room is shut tightly, letting in no breath of air - and letting out none of the thousands of mosquitoes that cover the walls and the man's body. Aedes aegypti is not the most common species along the Gulf Coast, but anyone with a course in medical entomology could build a simple trap and conscript a bloodthirsty army.

Across the hall, another man cracks his door and peers out. Seeing nobody in the hallway, he emerges wearing beekeepers' garb. After slipping into the sickroom, he watches as a convulsion wracks the martyr's body. The insects rise in a ravenous cloud, droning their annoyance at having their meal disturbed.

Taking advantage of the moment, the garbed man crosses the room and opens the window...

Insect-borne diseases were rampant in Civil War hospitals such as this one in Washington D.C. (Library of Congress)

Using insects as weapons of terrorism seems darkly fantastical but the history of entomological warfare suggests that such a scenario is frighteningly plausible. Jack Woodall, director of the Nucleus for the Investigation of Emerging Infections Diseases at the Federal University of Rio de Janeiro, warns that years of complacency and a focus on disease darlings (bird flu being a recent media favorite) have set up the American public for an outbreak - natural or otherwise - of yellow fever.

The potential for this disease to decimate a civilian population was understood by American military strategists in the 1960s. Biological warfare researchers drew up plans to produce 130 million infected mosquitoes per month. And they developed sophisticated delivery systems - including open-field tests on an unsuspecting American public (albeit with uninfected vectors).

A partially declassified "Entomological Warfare Target Analysis" from this time shows that the US Army was considering attacks on Soviet cities with yellow fever mosquitoes. The report concluded that it "would be impossible for a nation such as the USSR to quickly undertake a mass immunization program to protect millions of people." But surely we could amass such a public health campaign today, right?

Based on a natural experiment with an insect-borne virus, things don't look so good. When West Nile virus arrived in 1999, government agencies scrambled to explain and then control the disease. The technological might of the United States could not keep mosquitoes from spreading the disease across the nation.

A pretty pest. The Mediterranean fruit fly, if permanently established, could decimate California agriculture (Photo by Scott Bauer, USDA/ARS)

Given our losing battle against West Nile virus, the greatest concern is its African cousin, Rift Valley fever. This virus causes abortions in pregnant livestock, and young animals suffer 10 to 70 percent mortality. In 1977, a strain able to invade the human nervous system emerged in Africa. Of 200,000 Egyptians who fell ill, some 2,000 lost their eyesight and 598 died of encephalitis. Every region in the United States has a mosquito species capable of transmitting this disease.

Nor would it be difficult to introduce Rift Valley fever, according to Charles Bailey, director of the National Center for Biodefense at George Mason University. A person with $100 worth of supplies, a set of simple instructions, and a plane ticket from an afflicted African nation to the United States could introduce the disease with virtually no chance of being caught.

All of this might sound like post 9/11 hyperbole but for the history of insect weapons in the 20th century. We might doubt the Cuban, Chinese, and North Korean accusations that the United States launched attacks with a menagerie of insect vectors during the Cold War, but there is no doubt that Japan's Unit 731 waged full-scale entomological warfare against China in World War II - and were on the verge of launching similar attacks against US troops and the American public. Between plague-infected fleas and cholera-coated flies, nearly half-a-million Chinese were killed.

A cockroach-based cyborg developed by Garnet Hertz at UC, Irvine. Movements of the Madagascar hissing cockroach are transferred to a three -wheeled robot via a modified trackball (Courtesy of Garnet Hertz)

Is the United States prepared for an entomological attack? Not according to Robert Kadlec, staff director for the U.S. Senate Subcommittee on Bioterrorism and Public Health. He argues that rather than amassing defenses along our borders, we should fund a flourishing public health system that can detect and quash whatever comes.

A great strategic lesson of 9/11 has been overlooked. Terrorists only need a little ingenuity, not sophisticated weapons, to cause enormous damage. Armed only with box cutters, the terrorists hijacked planes and brought down the towers of the World Trade Center. Insects are the box cutters of biological warfare-cheap, simple, and wickedly effective.

...Sensing the air currents, a cloud of mosquitoes pours through the window, carrying a payload of yellow fever. The city's tropical heat, stagnant waters, crumbling infrastructure, decrepit health care system, and haggard people - nearly a quarter million resolute souls after Katrina - will provide an ideal setting for an epidemic. The man pulls a cell phone from his pocket and reads the coded text messages from his associates in Houston and Miami. He smiles, brushes a mosquito from the key pad, and dials the news desk at CNN.

Jeff Lockwood is the author of Six-Legged Soldiers: Using Insects as Weapons of War. Educated as an entomologist and originally working on grasshopper and locust management, he now enjoys a split appointment between the department of philosophy and the MFA program in creative writing at the University of Wyoming. As a professor of natural sciences and humanities, Lockwood explores the interface between scientific knowledge and human values, social practices, and philosophical understandings.

Six-Legged Soldiers: Using Insects as Weapons of War, Jeffrey A. Lockwood. Oxford University Press, New York, 2008 377 pp. ISBN: 978-0-19-533305-3. $27.95.

Correction (10/24/08) - In the original version of this story, the author's name was misspelled. The mistake has been corrected, and The Scientist regrets the error.