Review
“An exceptionally readable and accurate series of accounts of unhappy encounters between people and various kinds of biting and stinging animals, even including those of the human kind.”
— Andrew Spielman Sc.D., Professor of Tropical Public Health, Harvard School of Public Health, Department of Immunology and Infectious Diseases and coauthor of Mosquito.
About the Author
Pamela Nagami, M.D., is a practicing physician in internal medicine and infectious diseases with the Southern California Permanente Medical Group and a clinical associate professor of Medicine at The David Geffen School of Medicine at UCLA. She lives with her husband in Encino, California.
Excerpt. © Reprinted by permission. All rights reserved.
Bitten
1Invincible InvadersIn a chronic-care facility in Houston, Texas, on a routine morning check, nursing home attendants discovered one of their patients--a ninety-year-old woman who suffered from a weak heart and "moderately severe" dementia--fully conscious but covered with thousands of rice-sized insects. The tiny creatures had been crawling in and out of her mouth and swarming over her body, conceivably for hours. However, due to the woman's general debility, she had been unable to summon help. After the attendants washed away the creatures, they discovered multiple welts all over her body. Over the next six hours, the reaction spread to her lungs, and, despite attentive hospital care, she died.
The red fire ant, Solenopsis invicta, the species responsible for the woman's death, is one of over eight thousand species of ants worldwide. All ants are social insects, living together in colonies.They are heat-loving creatures--only a few species live in Alpine or arctic regions. The first fossil ants appear in European and North American rock strata dating back about sixty million years, around the same time that the dinosaurs were dying out.Ants have large heads and oval abdomens joined to the thorax by a narrow waist. The antennae have an elbowlike bend, and the mouth is equipped with two sets of jaws, the outer pair for carrying and digging and the inner set for chewing. Like their close relatives, the bees, many species have a powerful stinger at the tip of the abdomen, which in ants can be used repeatedly without damaging the owner.Solenopsis invicta is not native to North America. It arrived on ships from South America in the 1930s through the port of Mobile, Alabama. Since then, fire ants have invaded the southern and southeastern United States and Puerto Rico. Every year, between 30 and 60 percent of people living in these areas experience their painful stings. The ant grasps the skin with its tiny, powerful jaws, arches its body, and then injects venom through the stinger. If allowed to do so, the ant will rotate itself about its anchored head and create a whole circle of stings. There's an immediate burning sensation, followed by hours to days of intense itching. Virtually everyone who is stung by a fire ant reacts with a red welt that, over several days, turns into a pus-filled pimple. Up to half of the victims will experience larger local reactions, and occasionally surgical drainage and amputation are necessary because of complicating infections.Fire ant venom may be toxic to the nervous system, as illustrated by two cases reported by Dr. Roger Fox and his colleagues at the University of South Florida in 1982. The first patient was a thirty-nine-year-old tree trimmer who was cutting palm trees when roughly one hundred fire ants bit his arms and shoulders. Ten months later, about two hundred fire ants attacked his armsand shoulders, and the next workday about the same number of ants bit him again. Following this final attack, his right hand and forearm gradually became numb, and over the next thirty-six hours his wrist became weak. The hand returned to normal in a month, but no further information on the patient was available; after the last attack, he moved and left no forwarding address.The other patient in Dr. Fox's report was a four-year-old boy who was with his father, a neurosurgeon, when he was stung by twenty red fire ants on his right foot. A half hour later the child had two convulsions, from which he recovered without ill effects.The most dangerous physical response to a fire ant sting is called an anaphylactic reaction, which is the same kind of reaction some people have to bee stings. This is not surprising, since ants belong to the same insect order as bees, the Hymenoptera.An anaphylactic reaction begins with faintness, itching, chest tightness, and wheezing, and ends with a precipitous fall in blood pressure and sometimes death. In parts of the southern United States where fire ants are prevalent, fatal allergic reactions to their venom are more common than deaths from bee stings. In sensitive people, only a sting or two is necessary to provoke the reaction.A typical case was that of the thirty-one-year-old man who arrived in an emergency department in Augusta, Georgia, thirty minutes after a fire ant stung him on the thumb. He told the doctors that within two or three minutes of the sting he had a strange metallic taste in his mouth. Then there was a sudden pain in his temples--he called it "the worst headache of [his] life." He felt shaky and had a sensation of pins and needles all over his body. His heart pounded, and his face turned red. This man, however, had the presence of mind to swallow two tablespoons of Dimetapp before he came to the emergency room. The liquid antihistamine got into his bloodstream quickly enough to save his life.Others have not been as fortunate. In 1989, Dr. Robert Rhoades and his colleagues reported the case of a thirty-two-year-old junior high school teacher who succumbed to anaphylaxis following fire ant stings. The patient had suffered a severe reaction to a sting in the past and had consulted an allergist, who recommended a course of desensitizing injections to prevent another reaction. She had declined treatment and, some time later, she sustained ten stings to her feet and ankles. Immediately she began gasping for breath as the air passages in her lungs squeezed shut. Although she was still alive on arrival to the emergency room, an electrocardiogram showed signs of severe heart strain and lack of oxygen. Shortly thereafter, her heartbeat stopped. The doctors were unable to resuscitate her.This young teacher had such a severe allergy to fire ant venom that even one sting would likely have proved fatal. If such a highly allergic victim were to succumb immediately as the result of one or two stings, it is conceivable that, in the absence of history, the cause of death could remain unknown. Physicians in areas where fire ants are plentiful speculate that a certain percentage of unexplained cases of cardiac arrest may be caused by unseen fatal allergic reactions to stings.Although lethal reactions to fire ant venom are uncommon, they are only the smallest part of a larger problem. A 1971 survey of physicians in Alabama, Georgia, and Mississippi revealed that over a three-year period doctors treated ten thousand patients for fire ant stings. Probably at least ten times that number were stung but did not seek medical attention. An estimated one half to one percent of fire ant stings result in severe allergic reactions, and a 1989 survey of 29,300 physicians practicing in fire ant--infested areas identified thirty-two confirmed deaths due to sting-induced anaphylaxis. It is probably safe to say that this figure is an underestimation. In some patients, as in the elderly woman in thenursing home, whose case opened this chapter, it is difficult to determine whether their deaths occurred as a result of allergic reactions or simply from a lethal dose of venom due to multiple stings. In small children suffering a large number of stings, this distinction may be impossible to make, as in this tragic case, also reported by Dr. Rhoades.A healthy, sixteen-month-old girl was "bumped by the family dog" and fell into a fire ant mound. The child suffered innumerable stings over her entire body. Her mother, a registered nurse, brushed off as many ants as she could and then bathed the child to remove those remaining, but it was already too late. The girl began gasping, and the mother started mouth-to-mouth breathing and dialed 911. By the time she arrived in the emergency room, the toddler was in full cardiac arrest. After she spent six days on a ventilator machine without signs of brain recovery, life support was stopped, and the child died.But fire ants are more than a medical menace. They threaten agriculture, animal husbandry, native plants and animals, and even roadways and electrical installations. To understand this invading insect enemy, it is necessary to return to its homeland, the Pantanal. The Pantanal is the vast flood plain of the headwaters of the Paraguay River, which includes areas in southwest Brazil, eastern Bolivia, Paraguay, and northern Argentina.In the Pantanal, fire ants build four- to six-inch mounds along roadsides. One egg-laying queen controls each mound, and is supported by one to two hundred thousand sterile female workers. Unlike bees, which use their venom only for defense, foraging fire ants are stinging predators. They subdue other invertebrates, consume their body fluids, and return with these nutrients to the nest. Fire ants are omnivorous and adaptable. They are efficient scavengers, feeding on dead animals, plant tissues, seeds, and sap flows. Where aphids are plentiful, they may turn from hunters to herders,tending and milking these tiny insects for their sweet secretions.However, in their homeland, fire ant populations are limited by competition from other species of ants and by disease-producing parasites. When baits were set up in the fire ant's habitat in Brazil, only thirteen percent of the traps with ants contained Solenopsis invicta. Other species of ants were equally common.Over twenty species of viruses, fungi, protozoa, roundworms, and flies attack fire ants in South America. Thelohania, a one-celled animal, or protozoan, multiplies inside the abdomen of worker fire ants, filling them with debilitating cysts. A tiny roundworm may also infect the stomach of the ant. However, the most bizarre of the South American fire ant parasites are the gnat-sized phorid flies. The females dive-bomb fire ants and inject their eggs into the animal's body. When the larva hatches, it burrows into the ant's head, where it releases enzymes that cause the host's head to fall off. Inside the detached head, the larva continues to grow until it emerges as a mature fly.But between 1930 and 1940, some lucky colonies of red fire ants left all of this behind. Their nests were loaded, most likely as ballast, onto cargo ships carrying lightweight agricultural goods from South America to Mobile, Alabama. In Mobile, the accidental stowaways were unloaded so that heavy machinery could be stowed in the ship's hold for the return trip.Upon its arrival in the Mobile, Alabama, area, Solenopsis invicta found the soil already colonized with native ants as well as an earlier arrival from South America, Solenopsis ricteri, the black fire ant. By 1950, the native species had all but disappeared; black ants had been pushed out of many of their habitats or had formed hybrid tribes with the invaders.Fire ant mounds are bigger in the United States than in South America, and often stand a foot and a half high, with tunnels that may radiate out over a hundred feet. Colonies are larger,numbering up to four hundred thousand individuals, and there are about nine times as many mounds in infested areas of Alabama as there are in similar habitats in Brazil.The red fire ant is known as a "tramp" or "weed" species. It thrives in recently opened or disturbed areas. Following World War II, there was rapid population growth in the "Sunbelt," and fire ants quickly invaded land cleared for homes, recreational areas, and industry. A survey of the infestation in 1950 showed that ants had spread from the port area halfway up the border between Mississippi and Alabama. In 1957, the United States Department of Agriculture attempted to quarantine the species, but overlooked the spread of the ants hiding in nursery stock. By 1989, Solenopsis invicta had invaded all the southern states.The red fire ant can survive in areas where the average minimum temperature is 10 degrees Fahrenheit (about negative 12 degrees Celsius). They have recently been reported in California and, based on annual average temperatures, they could spread from Arizona, through Southern California, and along the West Coast as far north as the Canadian border.But it was not only the welcoming climate and lack of competition and of diseases that allowed the wildfire spread of Solenopsis invicta across the south. The red fire ant itself was changing in ominous ways, probably as a result of genetic mutations.Every fire ant colony begins with a queen, a winged, half-inch-long female who has mated with a winged male while in flight. Upon landing, the mated female sheds her wings and burrows three to ten inches into the earth, sealing the entrance with soil. Within one day she lays ten to twenty eggs, which give rise to the first workers, her attendants. If many newly mated females land in the same area, they may aggregate and found a colony together. However, as the colony becomes established, the workers will eventually execute all the queens but one. The workers thenfiercely defend the area around their mound from the incursions of workers from neighboring mounds. The number of mounds in a given area is thus strictly limited by the territorial instincts of red fire ant workers.However, in the early 1970s scientists in several locations began to report colonies with multiple queens. These colonies contain workers who, despite being genetically unrelated, cooperate over extended areas without territorial hostility. Mound densities increased three to ten times, and some mound systems contain millions of individuals.Once the red fire ants in a given area evolve these multiple-queen--or polygyne--colonies, other species of invertebrates cannot compete, and the ecological diversity of that environment is severely damaged. Sanford Porter and Dolores Savignano at the University of Texas in Austin studied a 32-hectare tract at the Brackenridge Field Laboratory near that city, using pitfall and bait traps to measure invertebrate abundance and diversity. At infested sites, the investigators found a ten- to thirtyfold increase in the total number of ants, of which over 99 percent were Solenopsis invicta. The abundance of isopods, mites, and scarab beetles declined severely, leaving the field to a few types of roaches, ground crickets, and beetles adapted to life with ants. Overall, there were a third fewer different species of invertebrates, and individual populations dropped to one quarter of their original size, pointing to severe ecological disruption by this foreign invader.Although red fire ants sometimes feed on agricultural pests, the damage they do to crops, particularly seeds and germinating seedlings, outweighs their beneficial role as insect predators. In addition, the presence of fire ant colonies in a field can lower crop yields, because the cutting bars of harvesting machinery have to be raised to avoid damage from the hard, heaped-up mounds.Fire ants will attack and kill a newborn calf, bird hatchling,disabled animal, or any confined animal that cannot avoid their stings. Furthermore, livestock may starve in the field when swarms of fire ants render their food inaccessible. Animals have been blinded by their attacks or suffered bites in mouth, rectum, or preexisting wounds. Even fish are not immune to the ant invasion; thousands of trout have died of venom poisoning after eating swarms of winged males and queens that have flown into lakes.Fire ants attack not only plants and animals. Attracted to the heated asphalt, they build mounds under rural roads, which then collapse as the undermined soil subsides. In 1977, a survey of forty miles of roadway in North Carolina revealed an average of twenty fire ant colonies per mile, with some undermining of the road at each location.Solenopsis invicta, the most pragmatic of creatures, has one peculiar trait. It is attracted to anything electrical. Fire ants, like bees, have tiny deposits of iron in their bodies and are, in fact, slightly ferromagnetic. But scientists are puzzled as to why fire ants enjoy being shocked by electric currents so much. Researchers at the University of Texas in El Paso set up special electric boxes, each with sixteen sets of copper points. They then put about four hundred worker fire ants in each box and turned on the current. Whether AC or DC, once the voltage reached fifty, the ants started swarming over the points. Even three hundred and fifty volts of direct current was not too hot for them. But it had to be electricity--electromagnetic fields, ozone, or wire insulation left the ants indifferent.In areas where they are plentiful, red fire ants will accumulate in the proximity of any exposed electric field. According to entomologist S. Bradley Vinson, "their numbers build up slowly on powered bare wires, contact points, and around fuses and switches." The ants not only swarm over wiring, they fill the devices with dirt. Fire ants have caused short circuits in telephone junction andswitching equipment, traffic control cabinets, power company transformers, airport landing lights, computers, flood control equipment, home wall plugs, and even car electrical systems. They foul contact surfaces, inhibit mechanical functions, and can cause electrical fires.Even homes are not safe. In South America, fire ants invade human habitations mainly during times of flooding or drought. But in the United States, perhaps because of the presence of wiring in walls, Solenopsis invicta nests are increasingly turning up in homes and apartments. In 1995, Drs. Richard de Shazo and David Williams reported the case of a thirty-nine-year-old woman and her nine-year-old daughter in Tampa, Florida, who, along with their dog and cat, were suffering repeated fire ant stings indoors. The family lived on the second floor of a wooden, three-story apartment complex. Despite repeated visits by the exterminator, fire ants persisted. When Dr. Williams, an entomologist, visited the building, he found colonies of red fire ants in the soil beneath the concrete slab foundation of the structure and also above the slab, in a first-floor corridor. Inside the apartment, the ants swarmed everywhere. Then Dr. Williams discovered along the wall of the living room a lump that had previously gone unnoticed. When he pulled back the carpet, he found a large mound of dirt--a colony of about fifty thousand ants.When fire ants build nests in homes or invade them on their foraging expeditions, a true ant horror can result. Fire ants make no distinction between a newborn calf and a newborn baby. They will attack any prey that cannot escape their stings, as in the following 1992 case from Birmingham, Alabama.A five-day-old boy was placed in a playpen six inches from the floor. The following morning, his parents found him pale, limp, and covered with ants. After quickly rinsing the ants off, they rushed him to a local emergency room. On arrival he was incardiac arrest. When the emergency room doctors inserted a plastic tube into his airway, they found ants in the back of his throat.After five minutes of resuscitation, the baby's heart began to beat. His doctors gave him epinephrine and antihistamines for anaphylactic shock and admitted him to the intensive care unit. He had approximately two thousand fire ant stings, and on one area of his forehead there was so much damage that a patch of his skin came off. The child was kept on a ventilator, but for the first sixteen hours he didn't move or try to breathe on his own. The infant's treatment was long and difficult. After five weeks in the hospital he was able to take formula from a bottle but was slightly spastic and did not follow objects well with his eyes. Six months after the attack, though the boy seemed to have recovered, he had some "mild delay in achieving motor milestones."In the seven decades since its arrival in the United States the red fire ant has defied all methods of eradication. This species, which has had various scientific names, was officially designated invicta, meaning "invincible," by the late W. F. Buren in 1965, because he felt that the species would prove almost impossible to manage.Dr. Buren's prediction has been abundantly borne out. Frantic farmers have poured gasoline onto fire ant mounds and set them on fire, but to no avail. Environmentally friendly but ineffectual home remedies have included wood ashes, citrus peels, watermelon rinds, vinegar, and grits poured or stuffed into mounds. In a review of the problem, Dr. Williams, the entomologist, records such "high-tech" solutions as microwave radiation, electrical probes, and explosives. Another remedy, he notes, is to dig up a mound and place it on top of another mound with the expectation that the ants will fight, eliminating both colonies. Without a bulldozer, this last scheme would be hard to implement without incurring hundreds of stings.Chemical control has been and continues to be the main weapon in the ant wars and, in fact, the fire ant crisis helped to create the environmental movement in this country. In August 1957, the U.S. Congress appropriated $2.4 million for imported fire ant control and, in October of that year, the Department of Agriculture began to show farmers how to drench ant mounds with the chlorinated hydrocarbon heptachlor. During the cold, wet winter of 1957-58, thousands of gallons of heptachlor were poured into the environment. Shortly afterward, wildlife and cattle began to die.In a 1961 effort to reduce the amount of pesticide needed to kill the ants, scientists at the Department of Agriculture Methods Development Laboratory in Gulfport, Mississippi, developed toxic baits. The researchers dissolved the powerful chlorinated hydrocarbon mirex in soybean oil, which they then used to soak corncob grits. Field studies showed that repeated applications of this pesticide resulted in excellent control of fire ant infestations.Then, in 1962, Rachel Carson published Silent Spring. Her warning of the adverse environmental impact of all chlorinated hydrocarbon pesticides, including mirex, led to studies in the late 1960s that showed that this pesticide biodegraded only very slowly. In 1970, environmental groups requested a court injunction to halt the use of mirex. Although their request was denied, that year the U.S. Department of the Interior banned its use on public lands they managed. Persistent pressure by environmental groups on the issue of pesticides led, in 1973, to the formation of the Environmental Protection Agency. In 1976, Allied Chemical Corporation voluntarily discontinued manufacture of mirex baits. A government nonprofit agency took over the factory and produced mirex until 1977, when the EPA was able to stop its use completely.But even before mirex was banned, it was clear that the redfire ant would never be contained, much less eradicated, from North American soil by chemical means. Control efforts still rely on baits laced with insecticide, but scientists have always hoped that biological methods of control might be brought to bear. Unfortunately, attempts to harness the known protozoan and fungal parasites of the fire ant have failed so far, because it has proved impossible to spread these diseases in ant colonies under experimental conditions. All ants are meticulous housekeepers and personal groomers. They recognize anything foreign in the colony and remove it immediately. In addition, some of the protozoan parasites are probably spread to the ants by some, as yet unidentified, intermediate host.Recently researchers in Florida have begun studying the phorid flies that lay eggs inside fire ants and make their heads fall off. If effective, they could be released into the wild. However, releasing one new species to attack another may backfire. The phorid flies could attack native insects or, separated from their own natural enemies, they, too, could multiply out of control.It seems, then, that the invincible fire ants will never be vanquished and will continue to extend their range in the United States. Patients and the doctors who treat them will have to be prepared for the consequences of their stings.Fire ant venom is a watery solution of organic compounds loosely termed alkaloids. They have a direct toxic effect on the membranes of mast cells. Paul Ehrlich, who later became famous for developing drug treatments for syphilis, discovered these curious cells in the 1870s. He found one form circulating in the blood stream and another living in the tissues. Stuffed with dense, blue-staining granules filled with histamine, both types act like tiny land mines. When a mast cell in the nose, for example, encounters a pollen grain, it explodes. The histamine provokes all the familiar allergic symptoms: runny, itchy nose and eyes, and sneezing. Ifthe allergen--from strawberries, for example, or shellfish--arrives via the blood stream, histamine release from mast cells in the skin causes hives. In the lungs, histamine provokes more serious reactions: spasmodic constriction of the bronchial passages with wheezing, coughing, and, in severe cases, an asphyxiating blockage of all airflow.Fire ant alkaloids are allergic mimics. They trigger histamine release from mast cells by direct membrane damage. No preexisting allergy is required. When stung by a fire ant, everyone develops the same kind of welts. In many people this local reaction, however massive, is all that occurs, as in the following patient.In 1971, two doctors from Houston, Texas, described the case of a forty-nine-year-old alcoholic who was brought to the hospital at two a.m. one Sunday morning. The man had been drinking all day and all night on Saturday and was on his way to a friend's house when he was overcome with drowsiness. Arriving in the dark at the ditch in front of the house he "selected a fire ant mound as his pillow." When his friend discovered him a few hours later, he had thousands of small black fire ants crawling on him. After the ants were washed off, the emergency room physicians found approximately five thousand fire ant welts on his face, torso, and extremities. Other than a strong odor of alcohol on his breath, the welts were the only abnormal finding on examination, and he survived without any other ill effects. The authors concluded, "After a night on the town, one should make an all-out effort to return home, for the fire ant is quite reluctant to share his bed with strangers."Life-threatening anaphylactic reactions are almost always triggered by substances that have a protein component. Bee sting venom, for example, is a complex mixture of various proteins, to which individuals become highly allergic after repeated exposures. For many years, ant-sting anaphylaxis was a medical mystery,because fire ant venom seemed to lack proteins. But it only takes an infinitesimal amount of allergen to trigger a fatal anaphylactic reaction and, in fact, there are proteins in fire ant venom, though they make up only one tenth of one percent of its weight.In 1979, Dr. Harold Baer and colleagues reported a meticulous chemical analysis of the contents of the venom sacs of Solenopsis invicta. It is possible to obtain minute amounts of venom by milking fire ants and collecting the fluid in tiny tubes. The investigators used Sephadex column chromatography, a method of analyzing solutions in which venom extracts are poured over beads to separate the different components. They found tiny amounts of the same set of enzyme proteins that bees have in their venom, and serum samples from patients with fire ant allergy showed strong binding of allergy-specific antibodies to several of the venom proteins. However, the specific proteins that trigger fire ant allergy are different from the proteins that trigger dangerous reactions to bee stings, which explains why patients who react to bee venom may or may not react to fire ant stings, and vice versa.The best treatment for anaphylaxis is by aborting the reaction by early treatment with epinephrine. Patients who have had severe reactions to fire ant stings should be prescribed epinephrine for self-administration. Products such as Epi-pen contain a dose of epinephrine preloaded into a pen-shaped syringe that can be administered subcutaneously with the push of a button. If the victim or the parent of a child with fire ant allergy can act quickly enough, a fatal allergic reaction can be diminished or delayed until paramedics arrive.It is better to prevent the reaction from occurring at all, and the most effective preventive measure for hypersensitive people who coexist with fire ants is immunotherapy. Already proven effective for bee sting allergy, immunotherapy for fire ant allergy was pioneered by Dr. R. Faser Triplett and reported in the SouthernMedical Journal in 1973. Dr. Triplett enrolled eighteen patients from the Mississippi Allergy Clinic in Jackson, each with a previous severe reaction to fire ant stings. Eight patients were under the age of four years. Of the eighteen patients, four had a past history of skin allergy or asthma before their first serious fire ant reaction, or had an anaphylactic reaction to a bee sting, and one had almost died following a wasp sting. The remaining twelve patients had nothing in their past histories to suggest a dangerous allergic tendency, but had received a warning with the first sting--hives, swelling of the lips or tongue, tightness in the chest, wheezing, or a fall in blood pressure.Because fire ant venom is so difficult to harvest in quantity, Dr. Triplett used an extract made from whole ants. In a series of injections lasting up to two years, patients received gradually increasing doses either once or twice weekly. Their bodies reacted by producing blocking antibodies that prevented the allergic chain reaction. Fire ants stung eight of the eighteen patients again, and all survived their repeat encounter without any dangerous symptoms.Immunotherapy with whole body extracts (WBE) of Solenopsis is now an accepted practice. But as immunotherapy is cumbersome, expensive, and time-consuming, doctors will usually perform a skin test to confirm allergy. Selected patients can be given an accelerated course of shots to provide protection faster, but the injections must still be given every year to maintain protection. For children and adults who must coexist with Solenopsis invicta despite serious allergy, these shots can mean the difference between life and death.No government agency or private concern will ever eradicate the red fire ant from the United States. And it is invading other countries, as well. In February 2001, fire ants attacked a workman at a container facility at the mouth of the Brisbane River inAustralia. According to genetic tests, the ants were a North American strain of Solenopsis invicta. Simultaneously, authorities discovered infestations several miles away in Brisbane's western suburbs. This strain of red fire ants came from South America, suggesting two separate incursions.For millions of years the red fire ant lived in the heart of the South American continent, cut off from contact with the outside world. Its life was supported and its population balanced within the ecosystem in which it evolved. But this isolation ended when North Americans, eager to exploit the region, breached the natural barriers, bringing their machines with them. There they encountered an invincible little adversary, as ruthless and resourceful as they were. And then, by accident, they brought it home.BITTEN. Copyright © 2004 by Pamela Nagami. All rights reserved. . No part of this book may be used or reproduced in any manner what-soever without written permission except in the case of brief quotations embodied in critical articles or reviews. For information, address St. Martin's Press, 175 Fifth Avenue, New York, N.Y. 100 10.
