Wicked Bugs

by Amy Stewart

  During World War II, scrub typhus was frustratingly hard to avoid. The mites lived in tall kunai grass, which grows to ten to twenty feet, and soldiers had no choice but to march through it. Burning down the fields of grass might have eliminated the mites, but this wasn’t always feasible in a war zone. The clothing the soldiers wore could hardly be sealed tightly enough to keep these tiny mites away. Soldiers who came down with the disease lost, on average, a hundred days of combat duty, as compared to only fourteen days for malaria cases. Twenty percent of them developed pneumonia, and one Army medical expert who treated the disease predicted that all of his patients infected with scrub typhus would live with permanent heart damage.

  Today scrub typhus infections still occur in parts of Australia, Japan, China, Southeast Asia, the Pacific Islands, and Sri Lanka. There is no vaccine available, and over a million people are infected worldwide.

  Meet the Relatives Members of this family include harvest mites and other tiny bloodsucking creatures. The larvae of many species of mites may be referred to as chiggers, but the so-called chiggers found in the United States are usually young harvest mites that do not transmit disease.

  PAINFUL

  Chigoe Flea

  TUNGA PENETRANS

  On Christopher Columbus’s second voyage to the New World, he established a colony on the island of Hispaniola, which is now home to Haiti and the Dominican Republic. Among the many problems he and his crew faced — a lack of supplies, food shortages, and battles with the local population — nothing was as troublesome as one small sand flea.

  SIZE:

  1 mm

  FAMILY:

  Tungidae

  HABITAT:

  Favors sandy, warm soil on deserts and beaches

  DISTRIBUTION:

  Tropical regions around the world, including Latin America, India, Africa, and the Caribbean

  Francisco de Oviedo, discussing Columbus’s voyages some thirty years later, wrote: “There were two plagues that the Spaniards and new settlers of these Indies suffered, which are natural plagues of this land. The first is syphilis, which was transferred and carried to Spain and from there to other parts of the world . . . and the other is the chigoe.” He went on to explain, with surprising accuracy for a sixteenth-century naturalist, the way the flea burrowed under toenails and laid its eggs there, creating what he described as “a small sack the size of a lentil, and sometimes like a garbanzo.” He noted that, while it was possible to evict the fleas with a fine needle, “many lost their feet because of the chigoe. Or at least a few toes . . . because it was necessary to cure themselves with iron or fire.” We can only assume that he meant that Columbus’s crew cut off their own toes, so desperate were they to rid themselves of this terrible infestation. Although early treatment with a sterile needle should have been simple, Oviedo wrote that “in the end, the Spaniards were not successful at this, any more than they were at curing syphilis.”

  Columbus’s crew cut off their own toes, so desperate were they to rid themselves of this terrible infestation.

  A female chigoe flea burrows into the skin of her host by simply tearing into it, living under the skin and dining on the host’s blood until she swells to about the size of a pea. She does not allow her host’s skin to heal over, maintaining an open wound so that she can breathe and also so she can receive male visitors when she’s feeling amorous. Sometimes her rear end can be seen in the center of the wound as a tiny black dot. She lays about a hundred eggs over the next week or two, and while those eggs are destined for the sandy beach the flea came from, they tend to stick to the wound, making for a truly appalling sight: clusters of tiny white eggs clinging to festering wounds. If left untreated, the eggs will eventually drop to the ground, and after the female has been in residence for about a month, she will die and fall out of the wound as well — but not before creating serious problems for the host.

  Tourists who get infested with the flea on some tropical beach usually do not experience this entire life cycle. They notice a lesion on their foot and get right to a doctor, where it can be carefully cleaned up, and the flea removed, before eggs are laid. But in poorer communities, people may live with dozens of these lesions on their feet, resulting in chronic infections, gangrene, and even the loss of toes. Because the fleas infest both people and animals, people who live in close contact with rodents or livestock face far more infestations than tourists strolling on the beach.

  One recent study at a favela in northeast Brazil showed that about a third of the community was infested with the fleas, a condition called tungiasis. Some people had over a hundred lesions on their feet, hands, and chest. The infestations were so bad that many of them had trouble walking or gripping anything with their hands. They had lost fingernails and toenails entirely. The researchers made a point of mentioning that local doctors did not observe or treat parasites like the chigoe flea unless they were specifically asked about it. While the idea of a doctor overlooking dozens of sores oozing the eggs of parasites seems impossible, it demonstrates how common the infestation is.

  Treatment for people participating in the study consisted of a simple cleaning, a tube of ointment, and the gift of a pair of tennis shoes to each patient — with a strong recommendation that they wear them.

  Meet the Relatives Related to other tiny fleas that infest birds and mammals, primarily in South America.

  HORRIBLE

  HAVE NO FEAR

  Entomologists Robert Coulson and John Witter analyzed the ways in which people respond to insects when they are out in nature. They described five different responses:

  Dead Insect Syndrome, in which people respond to insects almost automatically by killing them, especially around campgrounds or picnic tables.

  Perfect Leaf Syndrome, in which hikers and campers alert park managers if they see the smallest nibble in a leaf or a tree. (Given the fact that most insects must eat plants in order to survive, such bites are normal and expected.)

  Entomophobia, an irrational fear of insects that can cause people to avoid all contact with nature.

  No Reaction, a response from people who understand that bugs are part of outdoor life and should be tolerated.

  Environmentalist Response, in which people believe that insecticides should not be used in any situation and favor the protection of all bugs under all circumstances.

  Of these responses, entomophobia may be the most familiar to us. Most of us know what an attack of irrational fear feels like: dizziness, sweaty palms, tunnel vision, fluttering heart. An extreme phobia can bring on debilitating panic attacks. When it comes to a fear of bugs — who tend to show up unexpectedly and in the most unlikely of places — a phobia may also send people running out of the room, shrieking in terror. Worse, it can drive people to indiscriminate pesticide use, which often poses a far greater threat to human health than would the bugs they are eradicating.

  But car accidents? A British insurance company conducted a study in 2008 that showed that over half a million English drivers have had a car accident caused by a bug (or, more precisely, caused by the distraction of a bug in the car). Three percent of drivers surveyed said they never drove with their windows down for fear that a bug might fly in. The insurance company is developing a type of netting that could be stretched over car windows to keep bugs out.

  Psychologists help people overcome their phobias by a slow and careful process of desensitization. For an insect phobia, it might begin with a person drawing a picture of a bug. Over a few sessions, they might make that picture more and more lifelike, and eventually work up to looking at a photograph of the creature they fear. Then they might view a dead bug in a jar from across the room, moving gradually closer to it. Once it’s possible to look closely at the dead bug without panicking, a live bug might be placed in the jar instead. The more successful patients will eventually be able to tolerate the presence of a live bug walking across a table, and might even be able to have a conversation about the fact that most insects, spiders, and o
ther creepy and slimy creatures pose little real threat.

  Over half a million English drivers have had a car accident caused by the distraction of a bug in the car.

  But perhaps the first step is to identify the fear. The naming of a phobia is more art than science; psychologists only officially recognize phobias as a broad category and use the term to relate to any number of persistent and irrational fears. The practice of attaching a Greek or Latin word to “phobia” to create a more specific name for a particular fear was common in the nineteenth century but is not formally in use by psychologists today. Here are just a few of the terms that have been invented to describe a fear of bugs:

  DANGEROUS

  Cockroach

  BLATTELLA GERMANICA

  The Carmelitos Housing Project in Southern California opened to great fanfare in 1940. A band played “The Star Spangled Banner,” a flag was raised, and speeches were given extolling the virtues of this “new design for living.” An article written by a new resident proclaimed “Uncle Sam is my landlord!” It was not your typical housing project — the small townhouse-style apartments, each with their own patch of lawn, looked more like vacation bungalows than low-income housing for the poor. This enormous complex — 712 apartments in all — was one of the first of its kind to offer people a way out of the depths of the Great Depression.

  SIZE:

  Up to 15 mm

  FAMILY:

  Blattellidae

  HABITAT:

  Lives primarily around humans in homes and buildings

  DISTRIBUTION:

  Worldwide

  Twenty years later, health officials noticed a disturbing pattern emerging from the sprawling development: almost 40 percent of all hepatitis A cases in the community came from the Carmelitos Housing Project. At the time, a team of UCLA scientists happened to be testing a new, relatively safe insecticide they had developed called “Dri-die,” a silica dust that broke down the waxy cuticle on a cockroach’s body, causing it to dry up and die. The UCLA team tested their new insecticide at Carmelitos with astonishing results: 70 percent of cockroaches were killed. And while hepatitis A cases continued to increase in the surrounding community, they were almost completely eliminated at Carmelitos. Getting rid of the cockroaches saved the residents from a terrible disease.

  “Cockroaches are among the most dreaded of insects,” said UCLA’s I. Barry Tarshis when he announced the results. “But this has been because they are so associated with filth, hard to get rid of, and look repugnant. Now we have evidence the disgust people feel for them is more than a mere prejudice.”

  Before this study, there was little evidence to show that cockroaches transmit disease. Today public health officials know that because cockroaches live in and around human habitation and exhibit “communicative behavior” — meaning that they move between filth or contamination and human foods — they can transmit disease.

  As one of the oldest insects on the planet, dating back 350 million years, cockroaches have long been associated with humans. But, in fact, of four thousand known species, 95 percent of them live entirely apart from humans, in forests, under logs, in caves, under rocks in the desert, and in damp, dark habitats near lakes and rivers. The 5 percent that do live around people seem to be universally loathed, for any number of reasons.

  Cockroaches have no trouble finding their way into any house. They do have wings and some species are capable of short flights; they are known to land on a door and wait until it opens to get inside or to crawl in through any crack or opening. Whether they stay depends entirely upon housekeeping. They love a messy kitchen and bathroom, and once they’re in an apartment complex, the shared ductwork, sewer lines, and electrical wiring in multiple dwellings mean that they can easily travel from one to the next without ever going outside. One study showed that roaches in Arizona moved several hundred yards through sewer systems to enter a home. Once inside, cockroaches give off a telltale repulsive, musty odor.

  Cockroaches are one of the oldest insects on the planet, dating back 350 million years.

  They are omnivorous feeders with what scientists call “un-specialized chewing mouthparts” that make it easy for them to live alongside humans and feed off a wide variety of human waste. Spilled food, trash, and sewage all attract cockroaches, but they will even chew on book bindings and the paste on stamps. Although they don’t bite humans, medical entomologists have reported that they feed on “fingernails, eyelashes, skin, calluses of hands and feet, and food residues about the faces of sleeping humans.”

  All this shuttling between people, food, and garbage mean that roaches carry any number of pathogens around with them, including E. coli, salmonella, leprosy, typhoid, dysentery, plague, hookworm, hepatitis, staphylococcus, and streptococcus. When Cockroaches feed, they often regurgitate a little food from their crop, leaving behind bits of their last meal as they eat the next one. They also defecate as they move - and feed, depositing tiny brown droppings as small as flakes of pepper, all of which makes it easier to spread disease.

  If that isn’t bad enough, half of all people with asthma are allergie to cockroaches. Ten percent of nonallergic people also have some kind of sensitivity to cockroaches, with the most severe reactions causing anaphylactic shock. Roach allergens can survive the most thorough cleaning measures, including boiling water, changes to pH, and ultraviolet light. Curiously, a cockroach allergy can bring on cross-reactions to crab, lobster, shrimp, and crawfish, as well as dust mites and other bugs.

  But perhaps the most dreaded human-to-cockroach encounter is the legendary ear infestation. Although it sounds too horrible to be anything more than an urban legend, in fact, cases of German cockroaches crawling into people’s ears and getting stuck there have been well documented in medical literature. Emergency room doctors can pour oil in the ear to drown cockroaches, but often have a hard time extracting them afterward. Some doctors swear by a squirt of lidocaine, which irritates the roach so much that it can send it running out of the ear and across the room.

  Attempts to rid homes of cockroaches often lead to even more health problems: epidemiologists have noted that an increase in home pesticide use, and the overall exposure to the chemicals that results from using them in the home, can pose a more serious hazard than the bugs themselves do. Safer roach baits are available, but cleanliness and a well-sealed home are the best defenses. A recent study showed that the “juice” of dead roaches was an effective roach repellent, but this is not likely to catch on as a home remedy.

  Meet the Relatives There are roughly four thousand species around the world. Periplaneta americana, the American cockroach or Palmetto bug, is a very large roach found throughout the southern United States and along parts of the East Coast.

  DESTRUCTIVE

  Colorado Potato Beetle

  LEPTINOTARSA DECEMLINEATA

  Thomas Say, often considered to be the father of American entomology, traveled west as far as the Rocky Mountains in 1820 as part of a military expedition. It was his job to “examine and describe any objects in zoology, and its several branches, that may come under our observation. A classification of all land and water animals, insects, &c. and a particular description of the animal remains found in a concrete state will be required.” His team consisted of a botanist, a geologist, an assistant naturalist, and a painter. This was not an easy journey; the group faced severe water shortages, attacks from Indian tribes, illnesses and injuries, and the loss of horses and critical supplies. It is no surprise, then, that when he encountered a small striped beetle feeding on a tough little weed in the nightshade family, he made a record of it but didn’t consider it one of the major discoveries of the expedition.

  SIZE:

  9.5 mm

  FAMILY:

  Chrysomelidae

  HABITAT:

  Farms, fields, and meadows where nightshades are abundant

  DISTRIBUTION:

  North America, Europe, Asia, and the Middle East

  The Colorado potato beet
le was just one of over a thousand species of beetles Say described in his lifetime — but it didn’t earn the name potato beetle until later. By the mid-1800s, shortly after Say’s death, settlers moved into the area Say had explored and began farming there. When the beetles encountered potato crops for the first time, they gradually abandoned the buffalo burr, the wild potato relative they had been feeding upon, and went to work on potatoes instead. To the horror of the settlers, it soon became clear that the beetles could strip a potato plant of all its leaves, decimating a field of the crop. It then set about eating other members of the nightshade family, including tomato, eggplant, and even tobacco leaves.

  The Germans believed that Americans were dropping the beetles from planes as a form of aerial agricultural warfare.

  It moved rapidly across the United States, from Nebraska to Iowa to Missouri, Illinois, Michigan, and Pennsylvania over a span of only fifteen years. In 1875 a popular science magazine noted that the beetle “has inflicted so much damage, and caused so much alarm in the United States, that the prospect of its succeeding in crossing the Atlantic has raised almost a panic in some European countries.”

  This was a well-founded fear. European countries banned the importation of American potatoes to keep the beetle out, but by World War I it was impossible to avoid the accidental importation of agricultural pests as American troops marched across the continent. Now the beetle ranges across Europe and through important agricultural areas across much of the rest of the world.