Zombies, vampires, and witches are generally the subject of horror films, nowadays. But there are accounts of these beings wreaking havoc in the past. Chee-Lan Chan considers medical explanations for their mysticism

Perhaps the hideous one eyed and two headed monsters of Greek mythology are not as sinister as depicted? Are they actually casualties from the lottery of life? Cyclopia results from a loss of midline tissue in gestation causing either a single eye or a fusion of both the eye, while conjoined twins have one body and two heads due to the abnormal or incomplete splitting of the axial area of the germ disc. In an age where medicine is fast becoming the new religion, can it live up to its omniscience by explaining some seemingly unexplainable mysteries of life? Let us take a look at some other notorious antiquated beliefs.

Zombies, the "living dead"

The concept of the zombie originates from Haitian folklore; it is a being that has been raised from the dead by a boko, a voodoo priest, using black magic. It is believed that the sorcerer, after exhuming the corpse, passes a vial which contains the soul of this body underneath its nose, thus creating the zombie. Zombies can then be exploited by the bokos as slave labour or used to carry out immoral acts.

It is believed that zombies are the living dead, capable of physical activities: walking, eating, hearing, and even talking, but they have no cognitive abilities. They have no memory or knowledge of their condition. In order to prevent the dead from suffering this terrible fate the corpse must be buried face down, mouth against the earth, holding a dagger so it may stab any sorcerer who attempts to meddle with it. The mouth is often sewn up; a corpse can be raised up only if it answers to its name. Distractions are put in the tomb to prevent the body from hearing calls from the bokos; an eyeless needle will take an eternity to thread, as will counting the sesame seeds that have been scattered. The way to terminate the unfortunate being is to inject him with a special poison, strangle him, or fire a bullet into its temple. This must all be done from behind the zombie to prevent the slayer from being seen and reported back to the vengeful sorcerer.

Zombies are not a myth

It would seem that although the zombie is part of Haitian folklore it is not a myth. Recently some convincing cases of zombification have been seen and researched. It seems that contrary to belief, the zombie is not raised from the dead but rather created from the living. The boko poisons a living individual with a specific potion inducing the zombie state. It was discovered that there are three main components to the zombie potions: the crushed bones of a human, a puffer fish (Diodon holocanthus, Diodon hysterix, Spheroides testudineus), and a toad (Bufo marinus). Pharmacologically, the bones of the human seem to have no effects. The puffer fish, however, does. It contains the chemical tetrodotoxin in its skin, liver, ovaries, and intestines and also carries ciguatoxin, a toxin similar to tetrodotoxin. Ciguatera poisoning causes parasthesia with prickling around the lips, tongue, and nose, a tingling sensation in the extremities, malaise, gastrointestinal, cardiovascular, and nervous pain. Death may result from respiratory paralysis. It has been found that the toad contains a plethora of active chemicals, the most relevant of which is found in the skin. This chemical resembles those found in the African arrow poison which causes muscle relaxation, depresses the respiratory centre, and in large doses can cause death. If given in the correct doses it seems that ciguatera, tetrodotoxin, and the chemical in the skin of the toad could induce a state rather similar to that of the zombie. The notion of the physical capabilities of the zombie may stem from instances when the victim recovers from the poisons administered, is taken from the grave by the boko, and made to take a potion containing the plant Datura stramonium. This contains alkaloids such as scopolomine and atropine which induces amnesia as well as acting as an antidote to the zombie poison.

Vampires and blood drinkers

The vampire is an enduring figure. From the chronicles of classical history, pagan annals, the 19th century gothic novel, to present day cult television, the vampire's celebrity continues. The primary source of the vampire belief is not known, and since the documentation of the vampire is so diverse--every culture has its own belief in a malevolent, blood sucking, undead creature--it is hard to determine what the characteristics of the archetypal vampire are. The Western vampire has its roots in ancient Greece and its activities have been chronicled ever since. A vampire is created if dead people have not received a proper burial, if they have been bitten by a vampire, if they have met a sudden or violent death, if they have led an evil, immoral life, or if they have dabbled in the black arts. The vampire belongs neither with the living nor the dead, it is a soulless creature which has to suck the blood of the living in order to maintain itself (it has prominent incisors for this), with the werewolf and the bat as its first degree relation. It has a large sexual appetite, can be warded off either by garlic, its own reflection, or by religious paraphernalia--that is, holy water or a crucifix, and can be destroyed only by sunlight, a stake through the heart or beheading.

Does that description sound similar to the symptoms of a victim of rabies? Hydrophobia, photophobia, hypersensitivity to strong odours, and hypersexuality are all symptoms of advanced rabies. Could the prominent incisors of a vampire actually be a retraction of the lips along with clenched teeth caused by spasms of the facial, pharyngeal, and laryngeal muscles in rabies? What about the vampire's fear of its own reflection? In the days when rabies was rife, a man was not considered rabid if he could look at his own reflection in the mirror. The association of the werewolf and the bat to the vampire is suggestive of zoonosis and is another link of vampirism to rabies.

Do vampires still exist?

What of the concept that vampires are deceased yet continue to walk the earth? Before and during most vampire epidemics there was also a medical crisis. For example, during the Hungarian vampire epidemic between 1692 to 1694 many people were suffering from the Black Death. Because so many were seriously ill, there was much confusion and it was not uncommon for the very feeble to be prematurely buried because they had been presumed dead. If they were lucky they may have been able to escape from their graves, dying shortly afterwards anyway of the Black Death. If they were unlucky, after much struggling in their grave, they would have suffocated to death; the change in the position of the body alarmed those who had buried it and were now reopening the vault or crypt to admit another corpse. Either way, the bodies would have been bloodied from the tussle and it would appear that they had risen from the dead.

How do we explain the idea that vampires drank blood? It is interesting to note that in the 16th century, around the same time as the emergence of the Eastern European vampire epidemic, Elisabeth Bathory, a Carpathian countess, was killing countless virgins. She was attempting to fulfil the myth that drinking their blood could stave off old age and illness as well as retaining beauty. Combining the sight of bloated, "undead," bloody corpses with the knowledge of many bizarre cannibalistic incidents and rabid humans, does the idea of vampire seem so unjustified? Could the combination of rabies, premature burial, cannibalism, and religious import have created the vampire myth?

Witches

One of the most infamous historical events involving witchcraft are the Salem witch trials. The period from January 1691 to September 1692 resulted in the accusation and trial of more than 122 inhabitants of Salem village (now Massachusetts) and the further conviction, sentencing, and execution of 19. The abhorrence of this incident is not so much the fact these probably innocent people were being tried for witchcraft (we must remember that in the 17th century belief in witches was pedestrian). The cause for alarm was the rapidity of the propagation of fear through a community. This led to the condemning of individuals who perhaps were not collaborating with the devil, but were instead victims of accusers suffering from the earthly affliction of ergotism.

Ergot alkaloids occur naturally in a fungus, Claviceps purpurea. This infests most cereal crops: rye, corn, wheat, rice, sorgham, barley, oats, and millet. The alkaloids are 3,4-indole-substituted mycotoxins--that is, ergoline, lysergic acid derivatives, and clavine alkaloids. Their effects are mediated through 5-HT receptors, adrenoreceptors, or dopamine receptors. There are two types of ergot poisoning. Gangrenous ergot poisoning is characterised by vasoconstriction, cold or numb sensations, weak peripheral pulses, dry, gangrenous injuries to the extremities, and, eventually, autoamputation. Convulsive ergotism is characterised by sensations of hot and cold in the extremities, painful spastic muscular contractions, vomiting and diarrhoea, ravenous appetite, tingling and severe itching, livid skin colour, mania, delirium, convulsions, and visual and auditory hallucinations. Apart from ergot alkaloids the fungus also contains histamine, tyramine, acetaldehyde, acetylcholine, and isoamylamine, which contribute to its toxicity. Erogotism occurs when the contaminated cereal is used for food.

Claviceps purpurea thrives in damp cool surroundings. Reportedly, the winter of 1690-1 was cold but the following spring and summer were humid providing appropriate conditions for its growth on cereal crops. There had been a crop failure in Salem village so the inhabitants were forced to eat freshly harvested, possibly contaminated cereals. The distribution of those afflicted was non-random, the accusers mostly lived along the rye supply routes in town. Furthermore, several cows died during the trials; ergotism is a recognised problem among grazing animals. The afflictions of the accusers resemble those of convulsive ergotism; they complained of being pricked and pinched by the accused, apparitions of the devil, and were often stricken with violent fits. The ages of the afflicted are comparable to the ages of the other ergot poisoning epidemics.

Were the Salem witch trials a result of ergot poisoning? Were they a result of mass hysteria within one community? Or was witchcraft being used as a smokescreen for the conspiracy to perform genocide in Salem village?

As Hippocrates stated, "It is the business of the physician to know in the first place things which are to be perceived by the sight, touch, hearing, the nose and the tongue and the understanding." Medicine can certainly rationalise extraordinary mysteries through the analysis of physical evidence, but can it wholly explain them? God only knows.