Excerpt: 'Wicked Bugs'

Wicked Bugs

By Amy Stewart

Hardcover, 288 pages

Algonquin Books

List Price: $18.95

Assassin Bug

Triatoma Infestans

In 1835, a young Charles Darwin recorded a strange encounter with a bug in Argentina. He was near the end of his journey on board the HMS Beagle, a British naval ship charged with surveying South America. Darwin had been hired on to fulfill the roles of scholarly companion to the captain and ship's naturalist. The journey had already been fraught with peril: the captain was unstable and ill-tempered; the locals attacked the crew and robbed them; and most everyone was beset by illness or hunger at some point. Then, on March 25, Darwin himself became dinner for one of the region's bloodsucking insects. In his diary he wrote, "At night I experienced an attack (for it deserves no less a name) of the Benchuca, a species of Reduvius, the great black bug of the Pampas. It is most disgusting to feel soft wingless insects, about an inch long, crawling over one's body."

He also recounted an experiment in which several of his shipmates offered themselves up to the bloodthirsty beasts: "When placed on a table, and though surrounded by people, if a finger was presented, the bold insect would immediately protrude its sucker, make a charge, and if allowed, draw blood . . . This one feast, for which the benchuca was indebted to one of the officers, kept it fat during four whole months; but, after the first fortnight, it was quite ready to have another suck."

What Darwin didn't know — what no one knew at the time — was that the bite of some assassin bugs can transmit a fatal illness called Chagas disease. These large, oval-shaped insects belong to the family Reduviidae; within that family, there are about 138 species of the bloodsucking Triatoma genus worldwide, half of which are known to transmit the disease. Most are found in North and South America, although there are some species in India and Southeast Asia. They live quite comfortably alongside their hosts, hiding out in burrows and nests and feeding on small rodents or bats. They're not shy about moving into houses or barns, either. In some parts of Latin America, where palm fronds are used as roofing material, the bugs are inadvertently introduced to local households through eggs attached to the fronds.

Assassin bugs go through five nymph stages on their way to adulthood, drinking up to nine times their weight in blood during a single feeding. An adult female might live six months, and during that time, she'll lay one hundred to six hundred eggs, the precise number depending on how much blood she consumes.

In most cases, the bite of the assassin bug causes no pain. It may feed for just a few minutes or up to half an hour, its body growing engorged as it drinks. A home with a severe infestation might contain several hundred bugs, and in this case it would not be uncommon for as many as twenty bugs to feed on an individual person, taking one to three milliliters of blood per night. Health care workers visiting the homes of patients recognize the worst infestations of these bugs by the streaks of black-and-white waste products running down the walls.

The assassin bug's preference for feeding around the mouth of its victim has earned it the nickname "kissing bug"; unfortunately, it can be the kiss of death. In 1908 a Brazilian doctor named Carlos Chagas was studying malaria when he noticed this bloodsucking insect and decided to find out whether it was carrying any disease-causing microbes. What he found was a protozoan parasite called Trypanosoma cruzi that the bug takes in during a meal. The parasite develops and multiplies inside the gut of the bug, and is then excreted in its feces. People get infected by the disease not from the bite itself, but from the feces deposited on the skin of the victim while the bug feeds. Scratching or rubbing the bug bite pushes the waste into the wound, introducing it to the bloodstream. (North American assassin bugs wait to do their business until about a half hour after they have eaten, by which time they have moved away from the victim. This helps explain why the disease is less common in the United States.)

What is most remarkable about Chagas's discovery is that he found the disease inside the vector insect first, then went on to diagnose humans who were infected with it. Once he did, he realized that he'd stumbled across a fatal disease that seemed to be linked to colonization. As settlers cleared land in the jungle and built mud and palm-thatched huts, the assassin bugs that were already living in the jungle and carrying the disease from one rodent to another found themselves suddenly living among humans— a fantastic source of warm, rich blood. Although the locals had already named the bug — some called it vinchuca, which meant "that which lets itself fall" from the roof, and some called it chirimacha, which meant "that which fears the cold" — the disease caused by the bug was just starting to become widespread around the time Chagas discovered it.

The assassin bug's preference for feeding around the mouth of its victim has earned it the nickname "kissing bug"; unfortunately, it can be the kiss of death.

People who are bitten around the eyes develop a terrible swelling. Bites elsewhere on the body result in small sores that give way to fever and swollen lymph nodes. The disease can kill in its early stages, but most people go on to experience a symptomless phase, followed by extensive damage to the heart, intestines, and other major organs, which may ultimately be fatal. About three hundred thousand people in the United States live with Chagas disease, and eight to eleven million people throughout Latin America suffer from it. Although early treatment can kill the parasites, there is no treatment for the later stages.

Some historians speculate that Charles Darwin himself was infected with Chagas disease and ultimately died from it. This would explain some of the strange and complicated health problems that plagued him throughout his life. However, the fact that he seems to have suffered from some of the same symptoms before he encountered the assassin bug in Argentina argues against that theory. Requests to exhume his remains from Westminster Abbey and test them for Chagas disease have been denied, leaving the exact cause of his health problems a mystery.

Bugs of War

Fifty years ago, in response to the launch of the Soviet satellite Sputnik, the U.S. Department of Defense formed a forward-thinking research office called DARPA, the Defense Advanced Research Projects Agency. Since then, DARPA researchers have developed stealth aircraft, new submarine technology, and an early version of the Internet, among other things. And now they've turned their attention to cyborg insects.

The Hybrid Insect Micro-Electro-Mechanical System (HI-MEMS) seeks to implant computer chips inside caterpillars before they undergo metamorphosis into moths or butterflies. Scientists hope to use that 1 circuitry to remotely control the flight path of insects so that they can someday be used to fly into enemy locations and transmit intelligence without ever being detected.

While the HI-MEMS program sounds too strange and futuristic to be true, it is simply the latest in a long history of deploying insects in war. Entomologist Jeffrey Lockwood studies the use of bugs in warfare; his research reveals that even beloved insects like honeybees have been used with malicious intent.

Bees and wasps

Bees and wasps have been used as weapons for thousands of years. Hurling a beehive or wasp nest at an enemy is an effective way to create havoc and send even the fiercest warriors running. Mayans had been using them since 2600 BC; their legends describe the use of human dummies with a gourd filled with stinging insects for a head. Early Greek writings on warfare described the practice of building tunnels under enemy walls and releasing bees and wasps into the tunnels. The use of catapults to hurl hives over enemy walls dates back at least to Roman times and continued through the Middle Ages.

But bees weren't used only during ancient times. As recently as World War I, Tanzanians hid beehives in the undergrowth and rigged their lids with trip wires so that invading British troops would encounter them in their efforts to seize control of the area from the Germans.

One of the most intriguing uses of bees in warfare was recorded by a contemporary of Socrates named Xenophon. He described the use of poisoned hives in Greek warfare around 402 BC: "All the soldiers ate of the combs, lost their senses, vomited, and were affected with purging, and none of them were able to stand upright; such as had eaten a little were like men greatly intoxicated, and such as had eaten much were like mad-men, and some like persons at the point of death." The soldiers had, apparently, been given beehives filled with the honey of bees that had feasted on rhododendron and azalea, plants that produce neurotoxins so potent that they remain active in the honey. Those who eat the honey succumb to honey intoxication, also called grayanotoxin poisoning.

Assassin bugs

These bloodsucking creatures that transmit Chagas disease have been used as instruments of torture in so-called bug pits. The most well-known example comes from 1838, when a British diplomat named Charles Stoddart arrived in the city of Bukhara in Uzbekistan to try to win over the local emir and enlist his support in halting the expansion of the Russian empire. Instead of making friends, he was branded an enemy and thrown into the bug pit, a hole beneath the zindan, a traditional Central Asian prison. There he suffered the attacks of assassin bugs, which were kept alive in between prisoners with gifts of fresh meat. A stone chute delivered manure from the stables above, which further attracted bugs and generally made the pit a place of misery.

A fellow British officer, Arthur Conolly, tried to rescue Stoddart after a couple of years, but he, too, was thrown into the pit. The men were literally eaten alive; accounts of the few times they were seen aboveground describe them as covered in sores and lice. The insects did not kill them, however: to accomplish that, they were beheaded in a public ceremony in 1842.

Scorpions

Even when they don't sting, scorpions look terrifying. Pliny the Elder wrote in about 77 AD that the scorpion was "a dangerous scourge, and has venom like that of the serpent; with the exception that its effects are far more painful, as the person who is stung will linger for three days before death ensues." He added that the sting of a scorpion was "invariably fatal to virgins, and nearly always so to matrons."

In the ancient city of Hatra, not far from Kirkuk and Mosul in Iraq, scorpions were deployed by local leaders in about 198 AD. They were defending their walled city against an attack by Roman troops led by Septimius Severus. When the troops arrived, the leaders had filled clay pots with scorpions — probably collected from the surrounding desert — and readied these venomous bombs to hurl at their attackers. Herodian of Antioch, a Roman historian writing at the time, described the scene this way: "Making clay pots, they filled them with winged insects, little poisonous flying creatures. When these were hurled down on the besiegers, the insects fell into the Romans' eyes and on all the unprotected parts of their bodies; digging in before they were noticed, they bit and stung the soldiers." Although scorpions don't fly, historians believe that the bombs contained scorpions along with an assortment of stinging insects, perhaps also including bees and wasps.

Fleas

These tiny, bloodsucking carriers of bubonic plague have also been used as an agent of war. During World War II, Japan's biological warfare project, called Unit 731, developed a method for dropping bombs filled with plague-infected fleas into enemy territory. They tested it in Ningbo, a seaside town in eastern China, and Changde, a city on the Yuan River in Hunan Province. Both communities experienced outbreaks of plague as a result of those experiments.

An estimated two hundred thousand Chinese people died at the hands of Japan's biological agent program. An operation called "Cherry Blossoms at Night" would have released the fleas over California, but that plan was never executed. The Japanese military also conducted horrific medical experiments on prisoners, subjecting them to gas chambers, disease, frostbite, and surgery without anesthetic. Although evidence of these war crimes did come to light after the war ended, the United States granted immunity to doctors involved with the project in exchange for access to their research and data. As part of the agreement, the project was kept a secret. It was not until the mid-1990s that historians began to report upon the atrocities committed by Unit 731.

Reprinted with permission from Wicked Bugs, by Amy Stewart, published by Algonquin Books. Copyright 2011 Amy Stewart. All rights reserved.