The Book of Blood: From Legends and Leeches to Vampires and Veins

by Hp Newquist

  But some creatures do want human blood. Some of them fly, some crawl, and others slither. They often attack in the dark, and they are usually so silent, we never hear them coming. The one thing they have in common is that they have to puncture our flesh to get at our blood.

  Blood is their food.

  Creatures that drink blood are known as hematophagous animals (“hema” comes from the Greek word for “blood”). Despite their sinister habits, they are usually harmless, and we’re not even aware that they’ve bitten us until they’ve finished the job and moved on. But sometimes their bites can kill.

  The deadliest hematophagous animal is a creature you’ve seen hundreds of times. The mosquito.

  The mosquito is the most common bloodsucker in the world. There are more than three thousand species of mosquito, and they are found on every continent with the exception of Antarctica. The mosquito (its name means “little fly” in Spanish) is not only an annoying pest but also the world’s single deadliest creature.

  Female mosquitoes drink human blood in order to provide nourishment for their larvae.

  Only the female mosquito drinks blood. Males never do. This is because the female needs the sugar from blood to help her generate and nourish her eggs. After she has laid her eggs, the female can live on juice from fruit and other plants. But as soon as she is ready to produce more eggs, she needs blood.

  The mosquito finds you by using a complex system of heat sensors and carbon dioxide detectors. She can follow the carbon dioxide you exhale, and then use her heat sensors to locate the right spot on your skin. Color may also play a role in helping the mosquito zero in on the right target. No one is sure exactly why, but mosquitoes are attracted to very dark colors, such black and navy blue. This could be due to the fact that these colors absorb heat (light colors would reflect heat) or that they stand out from the greens, browns, yellows, and other colors that are more prevalent in nature.

  Once she lands on your flesh—so gently that you rarely feel it—the female goes to work. The proboscis, or pointed mouthpart, of a mosquito is designed like a hypodermic needle, which is the device doctors use to inject or extract blood from you during medical examinations. The mosquito uses this needlelike mouth to pierce your skin and drill into a capillary.

  The incredible part of this process is not the sharp mouth, but the saliva. A mosquito’s saliva contains an anesthetic that keeps you from feeling her mouth puncture your skin. It also contains an anticoagulant that keeps blood from clotting while she is sucking the blood out. This way, she can suck quickly without the blood’s getting clogged by platelets. (Scientists have begun studying the chemical makeup of mosquito saliva to try to develop similar anesthetics and anticoagulants.)

  The mosquito sucks as much blood from a capillary as she can, then pulls out and flies away. It is only after the anesthetic wears off that you feel the bite, and by that time your body is already reacting to it. Seeking to fight off the effect of the saliva, your skin creates the bump that we all know as a mosquito bite.

  The mosquito takes so little of your blood that your body never notices it’s gone. What makes the mosquito dangerous is that she goes from person to person and pierces him or her with her mouth—which brings the blood from one person into contact with that of another. This means that if the mosquito drinks the blood from someone with a disease caused by certain parasites, she can transmit them to the next person she bites through her saliva. This is like getting a disease by injecting tainted blood or using a dirty hypodermic needle.

  Unfortunately, the mosquito can carry some of the deadliest diseases in the world. Although many of these diseases, such as malaria, are treatable and are rarely found in industrialized countries, they are especially deadly in parts of Africa, Asia, and South America. These places have too few doctors and too little medication to treat the people infected by mosquitoes.

  * * *

  MOSQUITO DISEASES

  The mosquito can carry viruses and parasites that are disease carriers. These include malaria, which breaks down red blood cells and can block the flow of blood to the brain. It also carries the flavivirus, a nasty bug that is responsible for dengue fever (it causes internal bleeding), West Nile virus (which causes brain disease), yellow fever (which leads to vomiting of blood and coma), and eastern equine encephalomyelitis (which causes brain and spinal cord disease).

  Mosquitoes don’t transmit all diseases because not all viruses and parasites can survive the transmission process. For instance, the human immunodeficiency virus (HIV) that causes AIDS is actually digested and destroyed inside the mosquito.

  Mosquitoes are known as a disease vector, meaning they do not cause the actual disease but transmit and spread the disease by carrying it from one host to another. Mosquitoes themselves are never affected by the diseases they carry.

  A poster warning people of the danger of getting malaria from mosquitoes.

  * * *

  Every year, mosquitoes spread diseases that kill more than one million people—some health organizations think the number of deaths is closer to five million. If you add this number up every year, you’ll quickly discover that mosquitoes have been responsible for billions of deaths over the course of human history. It is likely that this tiny insect has killed more humans than all other animals combined.

  Like mosquitoes, most creatures that use human blood for food are insects. These include the bedbug (which has become an increasingly dangerous pest since the beginning of the twenty-first century, due in part to its resistance to pesticides), sand flies, horseflies, ticks, and fleas. Many of them also drink the blood of other mammals and don’t limit their bloodsucking to people.

  Bedbugs bite ... then drink your blood.

  The strangest animal to feed on blood is the leech. A large sluglike creature about the size of a big thumb and resembling a hugely overgrown snail without its shell, the leech is found in numerous countries. There are many species of leeches, not all of which suck blood, but those that do are found in both water and on land. They attach themselves to swimmers or to people who are sleeping in leech-infested areas such as swamps.

  Leeches latch on to you by using a long set of jaws that sink into your skin like a row of staples. Their saliva contains an anesthetic that minimizes—and sometimes completely prevents—any pain you might feel from the bite. Leeches also use a form of suction to hang on tightly to your skin. Once a leech is attached, it is very hard to remove it without hurting yourself. And the leech won’t let go until it’s finished getting what it wants.

  Leeches attach themselves to your skin and feed on your blood until they are full-then they drop off.

  Like the mosquito, the leech has anticoagulants in its saliva to keep your blood from clotting. This allows it a nice, constant supply of blood from the capillaries it has bitten into. Unlike the mosquito, though, the leech doesn’t take a quick gulp and move on. It requires enough blood to fill its entire body, and can swell up to about five times its normal size to get extra blood. This amount can range anywhere from a teaspoon to a tablespoon or more. It’s still not enough blood to affect your body, but it is incredibly gross and even frightening to think that this creature is locked onto your skin and drinking your blood.

  Leeches drop off once they are completely full. They can also be pried loose by doctors or by gradually separating them from your skin a tiny bit at a time. Ripping them off quickly can be painful and can cause an infection.

  In years past, sick people got to experience this bit of gruesomeness firsthand if they had doctors who believed in using leeches for bloodletting. Some doctors felt that leeches were safer than lancets and easier to use for draining blood. They just attached a leech—or a few—let it do its work, and when the leech was finished, it popped off.

  Though bloodletting never worked, surprisingly leeches turned out to be a good medical device. In just the last few years, leeches have been used to treat patients who’d undergone delicate surgery. In certain kinds of skin surg
ery—such as reattaching severed limbs—where there is a danger of capillaries’ clotting up and preventing skin from healing, doctors put leeches on the area to speed up recovery. This happens thanks to the leeches’ saliva.

  The leech is placed on skin by doctors. It affixes itself to the wound, and its saliva, as well as its natural bloodsucking, keeps the blood flowing normally. This prevents clots and gives the body a chance to grow new capillaries that will connect across the gap in the skin. These particular leeches are grown in labs and used specifically for surgery. Doctors may require the use of several dozen of them to accomplish what modern medicine still cannot.

  The vampire bat looks scarier than it really is and rarely harms its victims. The bat is made all the more frightening by the fact that it walks on the ground to get close to its victims, much like the “human” vampires in books and movies.

  The leech may be repugnant, but the most frightening hematophagous creature is the vampire bat. It is found primarily in Central and South America, and like all bats, it feeds at night. While most bats feast on fruit or insects, the vampire bat does indeed feed on blood. It will drink the blood of warm-blooded mammals, including cows, sheep, and humans.

  Bats are well known for their ability to use radarlike signals to detect their prey. They send out high-pitched squeals that bounce off their insect prey and are received back in their ears. This is called echolocation. It allows bats to quickly find food even while flying in the dark. The vampire bat has a variation of this function, allowing it to also recognize the sounds of sleeping creatures, based primarily on their slow and shallow breathing. You can do this, too, as you can probably tell if a person is sleeping or awake by the way he or she breathes.

  Once the bat has detected a sleeping human, it lands right near the body. Then it walks—yes, walks—over to the person and gently climbs up on him or her. Using a sensor in its nose, it finds a warm spot where blood is flowing just under the surface of the skin. This is often the carotid artery, which carries blood straight from the heart, up through the neck, and into the brain.

  The vampire bat has two razor-sharp front teeth, which it quickly sinks into the victim, who rarely notices the bite. Like all hematophages, the vampire bat’s saliva keeps the blood flowing once the puncture has been made (the vampire bat’s saliva is called Draculin, but more on that in the next chapter). Instead of sucking the flowing blood, the bat licks it up with its tongue. It does this for about half an hour, usually taking an ounce or more of blood from its sleeping prey. Although the amount isn’t enough to harm the prey, it’s enough to actually double the entire weight of the vampire bat while it feeds.

  When it is done, the bat walks away and then lurches into the air, flying back to join the hundreds of other bats that it lives with in a cave or tree. All that is left after it leaves its victim are the two puncture marks made by its fangs and a trickle of blood.

  Vampire bats can occasionally transmit diseases such as rabies or cause infections in the people they bite. That they can drink blood and make people very ill—all without waking up their victims—makes them seem like silent demons. The thought of a vampire bat climbing up on you is enough to give you nightmares.

  What if instead of a bat the vampire were actually a human? Someone who crept into your bedroom and sucked your blood while you slept? For many people, that might be the biggest nightmare of all.

  CHAPTER 10

  The Undead

  One of the first horror movies ever made was called Nosferatu. It was produced in Germany and released in 1922. It told the story of Count Orlok, a creepy and scary-looking man who drank the blood of his victims in the dark of night. Orlok drank the blood of humans for one sinister reason: he was actually dead, and needed fresh blood so that he could still walk among the living. This made him “undead.”

  Since that time nearly a century ago, vampires and the undead have been featured in hundreds of movies made all over the world.

  Bram Stoker, the man who wrote Dracula, has inspired countless vampire stories over the last century.

  Nosferatu is an adaptation of a book called Dracula, which was written in 1897 by an Irish novelist named Bram Stoker. Dracula is about a man from a mysterious place called Transylvania. His name is Count Dracula, and unbeknownst to those around him, he sleeps in a coffin during the day and sucks the blood of sleeping people during the night—just like a vampire bat.

  Stoker’s novel was based on the story of a prince named Vlad Tepes, a member of the royal family in what is now Romania, a country in eastern Europe. And the mysterious Transylvania is actually located in central Romania.

  Vlad ruled during the mid-1400s. His family was part of the Order of the Dragon, called Dracul in his native language (the word derives from “Draco,” the Latin word for “dragon”). Thus, he became known as Vlad Dracul.

  Vlad Dracul sits comfortably at a table, watching as his enemies are tortured and executed.

  Vlad was a particularly vile ruler. Many called him bloodthirsty. He thought nothing of having his enemies tortured and murdered right in front of him. It is believed that he was responsible for tens of thousands of killings during his reign. One of his favorite methods of execution was to have a sharpened pole driven through the chests of his victims—a ghastly process called impaling—and then propping up the poles for all to see. For this he became known as Vlad the Impaler.

  More than four hundred years later, Bram Stoker took some of the details of Vlad’s life and used them as elements in his story: the name Dracul, the setting in Transylvania, and the use of sharp stakes through the chest. According to Stoker’s story, the only way to kill a vampire was to drive a sharp stake through its heart.

  The Transylvanian prince Vlad Tepes was one of the inspirations for the story of Dracula.

  Vlad, however, wasn’t a vampire. He didn’t actually drink his victims’ blood. For that part of his book, Stoker used legends that had been told in Europe for centuries. Many cultures had stories of dead people who came out of graves to feed on the blood of the living. This enabled the undead to stay alive, if only at night. The horrific thing about the undead was that if you were bitten by one, you might become one of them.

  These legends highlight people’s fear of blood, and also its importance. After all, blood was considered powerful enough to help reanimate the dead. We know that blood was important in ancient rituals, and there were myths of gods who took blood from humans. The idea of people coming back from the dead to take blood from the living was particularly unusual, though. No one is sure exactly where these legends came from, but we do have a pretty good theory. And the legends go back to the plagues that ravaged Europe during the Dark and Middle Ages.

  One of the symptoms of particular forms of the plague is bleeding from the mouth. Even though they had no medical knowledge, people of the time realized that this was a bad thing, • and they ran away from those who bled. They knew these people had a disease and thought it might be a curse or a sign that bleeders were inhabited by the Devil. To keep from getting cursed themselves, they avoided these bleeders like ... well, like the plague. Some of them were thought to be witches.

  These were natural fears at the time, given the widespread lack of information, but by themselves they wouldn’t have given rise to the notion of the undead. Even though sick people were bleeding, they were still very much alive. Something more threatening was at work.

  A superstition arose that it wasn’t just the living who might be cursed or possessed by the Devil. It was the dead, as well. Corpses came out of their graves and preyed on the living, drinking their blood at night when no one could see them. Maybe if they drank enough blood, these corpses could come back to “real” life. But where did such an extraordinary idea come from?

  Researchers think they might have recently found the answer. In early 2009, the body of a woman was unearthed in Venice, Italy. She had died during a plague that had occurred in the 1500s in that city, and her body was in a mass grave. The
se graves are used during plagues or natural disasters when there is no time for proper burials because so many people die during such occurrences. The dead must be buried quickly before their bodies start to decay and possibly spread disease to those who are still alive.

  The skull of a woman with a brick wedged between her teeth. Researchers think that those who buried her might have believed she was a vampire.

  What made the finding of this woman so bizarre was that she was found with a brick wedged into her mouth. But why?

  The answer lay in other people who had been buried in mass graves. When people were buried, usually the only preparation was to wrap them in a large cloth called a shroud. This fit tightly around all parts of the body, especially the face and head. No other consideration, such as draining the body of its fluids or putting it in an individual coffin, was given. There was no time; too many other people had to be buried.

  Without proper preparation, something strange—but altogether natural—would happen to these bodies. They would swell from the gases still trapped in their organs. Some of their internal fluids, ranging from blood to bile, would be expelled from their mouths and noses (in the world of funerals and cemeteries, this is called purge fluid). This dark fluid would eat through the shroud like acid, leaving what looked like a bloody hole around the mouth.