by Amy Stewart
Serious infestations cause a strange thickening and discoloration of the skin known as vagabond disease, or pediculosis corporis. People also develop swollen lymph nodes, fever, rash, headache, joint and muscle pain, and allergies, simply from exposure to the lice. Once a person develops high temperatures, the lice will leave them and look for another, less overheated human host, increasing the likelihood of spreading disease.
One of the most common louse-borne diseases is typhus, which is caused by infection with Rickettsia prowazekii, a bacteria that also lives in the blood of flying squirrels. The bacteria aren’t actually transmitted by the louse’s bite. Instead, they are excreted in lice feces, which make their way into the bloodstream when people scratch their bites and inadvertently push the bacteria into the bite wound. Because the bacteria remain viable in lice feces for ninety days, opportunities for infection are plentiful. The disease causes fever, chills, rashes, and eventually delirium, coma, and perhaps death.
About 20 percent of typhus cases are fatal, although death rates are usually much higher during times of war. Survivors used to live with the bacteria in their lymph nodes for years. (Today’s modern antiobotics offer a full recovery.) While humans may survive a bout of typhus, the louse never does. The man who developed the typhus vaccine, Hans Zinsser, wrote: “If lice can dread, the nightmare of their lives is the fear of some day of inhabiting an infected . . . human . . . Man is too prone to look on all nature through egocentric eyes. To the louse, we are the dreaded emissaries of death.”
In addition to plaguing soldiers living in crowded, unhygienic conditions, the disease also spread to Native Americans after European contact in the 1500s, killing millions. Today outbreaks still occur, primarily in refugee camps, slums, and other areas of mass migrations, severe crowding, and poverty.
Lice were once thought to emerge naturally from the skin, as if born from humans. Aristotle wrote that “lice are generated out of the flesh of animals” and could be seen jumping out of “small eruptions” in the skin. The condition of lice infestation, called “lousy disease” or phthiriasis, was believed to be a punishment for sins. It wasn’t until 1882 that L. D. Bulkley put these myths to rest, writing that “all the fabulous stories in regard to lice issuing from abscesses or sores are utterly without scientific foundation—are, indeed, impossibly absurd.” A Danish entomologist named Jørgen Christian Schiødte wrote that “the ancient ghost of Phthiriasis could finally be laid to rest among the other dragons and monsters, bred by ignorance.”
HEAD LICE
Pediculus humanus capitis
Because lice have the strange ability to match the color of the skin on which they hatch, an infestation of head lice can be hard to detect—an unpleasant surprise, but not a particularly dangerous one. Head lice do not transmit disease; their presence is not even a sign of uncleanliness. But they are infuriatingly difficult to get rid of and surprisingly common—second only to the common cold in communicable diseases that afflict schoolchildren. An estimated six to twelve million children are infested every year, or about a quarter of all children in the United States. African American children are mostly spared the annoyance of head lice; American lice find it difficult to grip coarse or curly hair, although African lice seem to have no problem with it.
Female head lice lay their eggs along a strand of hair, excreting a little cement to secure them in place. (In fact, a hazard of motherhood for a female louse is the risk of accidentally gluing oneself down as well.) They prefer to deposit their young around the ears or the neck, and this is where they can be most easily seen. Although special medicated shampoos can kill lice, in some parts of the country the lice are growing resistant to those chemicals. A new generation of prescription creams and shampoos are available, but many parents resort to the old-fashioned approach of running a fine comb through wet hair coated in vegetable oil to remove the nits, one at a time.
Poverty, overcrowded conditions, and warfare led Lenin to say, “Either socialism will defeat the louse, or the louse will defeat socialism.”
PUBIC LICE
Pthirus pubis
Pubic lice, also known as crabs, lock their claws around a strand of hair and almost never let go. Their habit of feeding in one place for most of their life means that their feces accumulate around them, making for a truly unpleasant situation. They inhabit all parts of the body covered in coarse hair, including eyebrows, chest hair, mustaches, armpits, and, of course, pubic hair. An allergic reaction to their saliva causes unbearable itching, which is usually the first sign of an infestation. They can also infest eyelashes, a condition known as phthiriasis, but they are not known to transmit disease.
Because pubic lice can only survive a few hours off the host, transmission via toilet seats, hotel bedspreads, and other such innocuous means is theoretically possible but unlikely. Sexual contact is really the most efficient means of transmission, which is why the French call pubic lice papillons d’amour, or butterflies of love.
PAINFUL
Spanish Fly
LYTTA VESICATORIA
It has been called “the scandal of the poisoned sweets.” In June of 1772, Marquis de Sade arrived in Marseilles and sent his valet out in search of prostitutes. The valet was able to convince several women to visit his employer over a single day, hardly an unusual arrangement for Sade. When the women arrived, he offered each of them anise-flavored candies. Some of the women accepted the candy; others refused. (For that matter, some of the women refused to do any number of things Sade proposed, including whipping him with a broom made of twigs.)
Over the next few days the women who had eaten the candy grew seriously ill, vomiting what was described as vile black matter and complaining of unbearable pain. The police got wind of the incident and charged Sade with sodomy and poisoning. He ran off to Italy to avoid imprisonment, but was arrested in December. He escaped in the spring and managed to avoid the law until 1778, when he was arrested again. He would remain in prison for over a decade.
SIZE:
25 mm
FAMILY:
Meloidae
HABITAT:
Meadows, fields, open woodlands, and farms
DISTRIBUTION:
North and South America, Europe, Middle East, Asia
The candy that got Marquis de Sade into so much trouble contained the powdered remains of a beautiful iridescent green beetle known as Spanish fly, intended as an aphrodisiac. A contemporary of Sade’s described the insect’s supposed effects: “All who ate them were seized by shameless ardor and lust . . . The most modest of women could not restrain themselves.”
The myth of Spanish fly’s aphrodisiac powers comes from the defensive chemical it secretes, cantharidin. When ingested, it inflames the urinary tract so much that it can cause a painful and long-lasting erection known as priapism. In sufficient quantities it leads to inflammation of the digestive tract, kidney damage, and even death. Marquis de Sade—and countless others—had confused this condition with sexual arousal and mistakenly believed that it would have a similar effect in women.
The candy that got Marquis de Sade into so much trouble contained the powdered remains of a beautiful iridescent green beetle known as Spanish fly, intended as an aphrodisiac.
The Spanish fly, also known as a blister beetle, uses its poison to repel predators. It also plays a role in reproduction: cantharidin is passed from males to females during mating, and the females use it to protect not just themselves but their eggs as well. In a peculiar way, the poison serves as an aphrodisiac for another species: a fire-colored beetle called Neopyrochroa flabellata that doesn’t produce any cantharidin itself, but actually takes it from blister beetles and uses it to attract a mate. Females of the species will refuse a suitor who doesn’t bring a package of this poison to her so that she can use it to protect her young.
Some blister beetles do manage to get eaten in spite of their chemical defenses. In 1861 and 1893, there were medical reports of French soldiers stationed in North Africa who ex
perienced priapism after eating frog legs. Scientists have long wondered if Spanish fly could have been involved. Cornell entomologist Thomas Eisner cleared up this medical mystery when he fed the beetles to frogs in the laboratory and then demonstrated that cantharidin was found in the frogs’ tissues at levels high enough to cause these painful and distressing symptoms. It appeared that the frogs would have to be eaten shortly after they had been feeding on blister beetles, which would explain why eating frog legs for dinner remains a low-risk activity.
The beetles themselves also pose a risk to livestock: some species feed on alfalfa hay, which means that they may inadvertently be fed to horses. Because the larvae eat grasshopper eggs, farmers and ranchers know that a large grasshopper population may mean an increase in blister beetles as well. It would take only a hundred blister beetles to kill a twelve-hundred-pound horse, and even smaller quantities cause colic. Because it is almost impossible to eradicate the beetle, alfalfa fields have to be monitored and mowed according to a specific set of guidelines designed to minimize the likelihood of beetles ending up in the hay.
Meet the Relatives Three thousand species have been identified around the world, with about three hundred found in the United States.
PAINFUL
Tarantula
THERAPHOSA BLONDI
Carole Hargis may well be the most inept murderer California has ever seen. In early 1977 she grew disenchanted with her marriage to David Hargis, a Marine Corps drill instructor stationed in San Diego. He had taken out a life insurance policy on himself, figuring that a military man could face danger at any time and he should make sure that his wife (and her children from a previous marriage) would be taken care of. Carole told her neighbor about the insurance policy and soon the two women hatched a plan to kill David and share the proceeds.
SIZE:
Up to 30 cm, including legs
FAMILY:
Theraphosidae
HABITAT:
Forests, foothills, and deserts, primarily in warm climates
DISTRIBUTION:
North and South America, Africa, Asia, Middle East, Australia, New Zealand, and Europe
The dozen or so murder plots they conceived would be comical if they hadn’t ended so tragically. First, Carole was inspired by an episode of Alfred Hitchcock Presents in which someone was killed by a hair dryer dropped in the bathtub. She tried that stunt—except that David was in the shower, and there wasn’t enough water to shock him. Then she mixed a powerful dose of LSD into his French toast, which only gave him a stomachache. Other plans involved bullets in the carburetor, lye in his martini, sleeping pills in his beer, and a car accident. She hoped to inject an air bubble into a vein while he slept, but the tip of the needle broke, and he awoke in the morning with what looked like a tiny insect bite.
She removed the tarantula’s venom sac and hid it in a blackberry pie. Her husband took a few bites of pie but never touched the venom. It was beginning to seem like he was invincible.
And then there was the tarantula pie. Carole kept a pet tarantula and at first she considered putting the hairy spider in bed with him, hoping he would get bitten. But then she had a better idea: she removed the tarantula’s venom sac and hid it in a blackberry pie. Mr. Hargis’s luck held out a while longer: he took a few bites of pie but never touched the venom. It was beginning to seem like he was invincible.
Eventually, Carole and her neighbor grew desperate and resorted to an old-fashioned bludgeoning, beating him to death in his bed and dumping his body in the desert, where they hoped it would look like an accident. It did not. The police had little trouble discovering the truth, and the women were tried and convicted for their crimes.
Among the many mistakes Carole Hargis made was her misunderstanding of the lethality of a tarantula’s venom. Not that they aren’t intimidating: the largest tarantula, Theraphosa blondi, spans almost a foot in length with its legs outstretched. It spins a trap and waits for its prey to walk by—a mouse, perhaps—then it pounces. With fangs almost an inch in length, it injects its venom and kills the mouse. And like some other tarantulas, it is covered in urticating (stinging) hairs, which it can rear up and fling at an enemy when threatened.
But in spite of this fearful behavior, the bite of a tarantula is really no worse than that of a wasp or a bee. It will certainly sting—in fact, scientists recently discovered that the bite of the West Indian tarantula Psalmopoeus cambridgei goes to work on nerve cells with the same mechanism employed by habanero peppers. That fierce, hot pain is hard to bear, but not fatal. For people with severe allergies, the venom can be quite dangerous, but most people will survive it.
In addition to its role in this strange murder case, the tarantula has long been associated with the Italian tarantella dance, which gets faster and faster as it progresses until it is quite frantic. “Tarantism” was a kind of dancing mania found in southern Italy during the fifteenth, sixteenth, and seventeenth centuries that was believed at the time to have been caused by the bite of a tarantula. But in fact, it was more likely caused by ergot poisoning (a fungus that infests rye and contains a precursor to LSD), or it could have been the result of some kind of mass anxiety or hysteria. Regardless, it is highly unlikely that the tarantula is to blame.
Meet the Relatives Over eight hundred species of tarantula are known worldwide.
DEADLY
Tsetse Fly
GLOSSINA SP.
In 1742 a surgeon named John Atkins described a condition he called the “Sleepy Distemper.” It afflicted slaves taken from West Africa and seemed to come on with no warning other than a loss of appetite, followed by a state of sleep so deep that not even a beating would awake them. “Their Sleeps are sound,” he wrote, “and Sense of Feeling very little; for pulling, drubbing, or whipping, will scarce stir up Sense and Power enough to move; and the moment you cease beating, the Smart is forgot, and down they fall again into a state of Insensibility.”
When beatings fail, the doctor advised, one must try anything to awaken them. “The Cure is attempted by whatever rouzes the Spirits; bleeding in the Jugular, quick Purges . . . and sudden Plunges into the Sea, the latter is most effectual when the Distemper is new and the Patient not yet driveling at Mouth and Nose.” He had to admit, though, that none of these torturous methods really worked and the disease was usually fatal.
SIZE:
6–14 mm
FAMILY:
Glossinidae
HABITAT:
Found in rain forest, savanna woodlands, and thickets
DISTRIBUTION:
Africa, particularly in the south
Atkins attributed this strange affliction to everything from “a Super-abundance of Phlegm” to what he saw as the general indolence and inactivity of the slaves, to “the natural Weakness of the Brain.” It did not occur to him to investigate the activities of a large, annoying fly that made a tse-tse sound as it buzzed around. It would be over one hundred years before the true cause of sleeping sickness was known.
The tsetse fly is found primarily in Africa south of the Saharan desert. Both male and female flies require blood meals to survive. There are about thirty species of the fly, which attack humans on different parts of their bodies. Glossina morsitans, for instance, will bite anywhere, while G. palpalis prefers to feed above the waist, and G. tachinoides generally attacks below the knee. Most tsetse flies are attracted to bright colors; wearing neutral clothing is one way to ward them off.
The flies feed on the blood of wild game, livestock, and humans, sometimes transmitting a protozoa of the genus Trypanosoma from one infected creature to the next. The disease moves into the lymphatic system, causing an extreme swelling of the lymph nodes known as Winterbottom’s sign. The infection finds its way into the central nervous system and brain, causing irritability, fatigue, aches, personality changes, confusion, and slurred speech. Left untreated, a person may be dead within six months, usually from heart failure.
Although the fly has been around for at least th
irty-four million years, the disease it transmits was mentioned only occasionally in early medical writings. It was not until European explorers began moving large expeditions of animals and workers through the African continent that sleeping sickness, called trypanosomiasis, became widespread. In fact, Henry Morton Stanley, the man who found David Livingstone in Africa in 1871, traveled through Uganda with a large party of cattle and men, followed by the tsetse fly, which accompanied the expedition because of the easy food source. He left an epidemic of sleeping sickness in his wake that wiped out as much as two-thirds of the region’s population.
There are two forms of the disease, one found in East Africa and another found in West Africa. It is estimated that fifty thousand to seventy thousand people may be infected with the disease today, but that number was ten times as high just a decade ago.
Henry Morton Stanley, the man who found David Livingstone in Africa, left an epidemic of sleeping sickness in his wake that wiped out as much as two-thirds of the region’s population.
One strategy for controlling the disease focuses on the tsetse fly itself. Scientists at the International Atomic Energy Agency have found some success with a “sterile insect technique” that involves raising male flies in a laboratory, exposing them to radiation to render them sterile, then releasing them to mate with females, who would then finish their life cycle without actually reproducing.
Unfortunately, the medications available for people infected with sleeping sickness are almost as dangerous as the disease itself. One drug, eflornithine, was originally developed as a cancer treatment and was later found to work against the West African form of sleeping sickness. Because it was so expensive to manufacture, the drug company took it off the shelves in the 1990s, but it started manufacturing it again a few years ago after pressure from the World Health Organization. Recently, a new and more commercially successful use for the drug has helped to spur its production: it is the active ingredient in a new facial cream used by women to treat unwanted facial hair. With a profitable cosmetic use for the drug, it is now once again available to treat sleeping sickness.