Vampires are fictional characters, protagonists of many films, books and other art productions. However, a few centuries ago they were considered a real threat by many people. This article was developed from reviews of scientific publications that raised hypotheses regarding the origin of the myth of vampirism, including research for possible links with historical facts.
According to the ‘Funk & Wagnalls Standard Dictionary of Folklore, Mythology, and Legend,’ “vampires” are defined as living-dead or soulless bodies that, from their place of burial, would seek the blood of the living to drink. Belief in vampires is widespread, but it is strongly integrated into the Slavic culture. In mid-eighteenth-century Hungary, belief in vampires was so strong that it can be compared to the witch-hunt period that occurred during the colonization of New England.
According to current folklore, vampires do not rest in their graves and spend the night looking for victims in which to bury their fangs and drink their blood. But when the rooster crows, the sun rises or bells toll in the morning, they return to their coffins — sunlight is supposedly an important source of discomfort for such creatures. Bells, mirrors and garlic are also considered effective weapons against vampires. According to popular culture, anyone bitten by a vampire becomes one of them after death. In this transformation process, the body is preserved from decomposition and the individual retains the appearance of a living person, with red mucous membranes and blood stains around the mouth. These creatures can only be exterminated if beheaded, burned, buried, or hit with a wooden stake driven through their hearts. Based on historical concepts, it is possible to establish existing biological relations between some diseases as the basis for the myth of vampirism.
According to the theory proposed by David H. Dolphin, the mystery of vampires has its origins in the Middle Ages, in Bohemia. This is considered a historic location in Central Europe and it currently corresponds to a large part of the Czech Republic. In Bohemia, several small communities were completely isolated, either by the scarcity of roads and means of transportation or, also, by the very division into fiefdoms. Individuals were not aware that there was an unexplored world beyond the borders of the mountains that surrounded their villages. These communities were forced to practice inbreeding, which led to a lack of genetic diversity.
The lack of genetic diversity in these isolated villages of Bohemia could have led to an increased local prevalence of certain diseases. Among them was porphyria (from the Greek “porphiros,” purplish-red), which causes the emergence of several signs that overlap with the physical traits of vampires. Thus, individuals suffering from porphyria have an anaemic aspect, with exacerbated paleness, and resemble vampiric figures.
Porphyria results from a deficiency of specific enzymes of the heme biosynthesis pathway, which prevents the chemical structure called porphyrin ring from binding to iron to form haemoglobin. The porphyrin rings, unable to carry out their task, are deposited in the subcutaneous tissue, bones, and teeth. This chemical substance is photoreactive and upon exposure to sunlight releases oxygen radicals, which are caustic and corrosive to the skin and can cause burns. Interestingly, this would be the reason behind vampires’ aversion to sunlight. Moreover, these creatures are characterized as having a nocturnal and gloomy behaviour. If the more serious manifestations are not treated, these lesions may cause disfigurement. Among them, mutilated ears and noses, deformed lips and retracted gums that reveal red teeth that appear larger than they truly are and thus similar to fangs. This last change is what appears to be the origin of the image of the vampires’ huge canines.
Legends also mention that vampires are repulsed by garlic. This plant has a volatile substance called diallyl sulfide which is very homologous with organic substances that promote changes in hepatic enzyme activity through the destruction of the heme groups. The products of heme destruction that compose the enzyme promote inhibition of the ferrochelatase, which participates in critical reactions in the synthesis of the heme itself: it catalyzes the insertion of iron into the protoporphyrin IX. When inhibited, it becomes a limiting factor for the synthesis of haemoglobin since protoporphyrin IX is the direct precursor of the heme. As a result, the heme group precursors accumulate because synthesis of porphyrins through negative feedback does not happen in this metabolic pathway. Changes in this metabolic pathway associate with the severity of the clinical manifestations of porphyria.
Another feature identified in vampire legends is the desire for blood, that is, these creatures’ search for “vital energy.” It is known that bloodletting was a common practice among ancient peoples, such as the noble families of the Balkans. However, they compensated the effects of bloodletting by slaughtering animals to ingest their blood. This behaviour of “sucking the blood of the prey” was probably incorporated into the making of the myth of vampirism.
The Belgian dermatologist Jean Goens based his theory on the following sentence: “Facts have been augmented and deformed by popular imagination until they eventually turned into sinister legends.” Jean Goens observed patients with porphyria and identified them as having mental disorders that resulted in antisocial behaviours, aggressiveness and a desire for isolation — misanthropy. These symptoms determined a markedly eccentric behaviour. Over the centuries, in the popular imagination, individuals affected by porphyria were considered “cursed beings,” or even “demons.” This interpretation was reinforced mainly by lack of knowledge about the pathophysiology of porphyria.
According to accounts in popular literature, vampires are often associated with the aristocracy or members of the nobility. This may have originated from the fact that porphyria worsens with sexual maturity (usually around age sixteen to seventeen). Coincidentally, that was the age at which the young women in these communities got married.
In the communities in Bohemia, where the myth is believed to have originated, there is a passage that reinforces the description above. The local leader would marry a virgin. After that, shortly after this young woman settled in her husband’s castle, she became pale and began to suffer the effects of porphyria. This event was interpreted by the local community as a habit of the feudal lord, a “creature” capable of sucking the blood of his own wife. Throughout the generations, this legend became increasingly distorted and implausible.
Other clinical conditions were also associated with the mythical figure of the vampire. The most noteworthy example could be pellagra. It was speculated at times that this disease, caused by a nutritional deficiency of niacin (vitamin B3) could explain the emergence of the popular belief in vampires.
A significant historical growth in the number of cases of pellagra has been recorded from the first half of the seventeenth-century. This fact can be attributed to the introduction of maize flour, which became the primary energy source in the diet of poor Europeans and has low niacin bioavailability. The clinical manifestations of pellagra were also related to vampires, but are nonspecific and do not contribute to explaining many of the features found in these mythological creatures. This disease is characterized by the triad dermatitis, dementia, and diarrhoea. The aspect of the skin in that entity is probably the factor that most relates to the myth of vampirism. It is known that individuals with pellagra are hypersensitive to sunlight. After being exposed to the sun, affected individuals develop reddish and hyperkeratotic lesions that eventually undergo depigmentation alternated with rough, brown-coloured areas. In conjunction with glossitis, which would result in changes in the teeth’s aspect and inflammation of the lips among individuals with pellagra, reinforcing the description of vampires as having “sharp, protruding teeth” and “prominent red lips.” Finally, pellagra dementia could explain other traits of the vampire profile: insomnia, irritability, impulsiveness, sluggishness and unpredictable behaviour.
Since the eighteenth-century, when these stories became popular, the image of the vampire has remained consistent. A timeless image linked to corruption, power, and gloom. However, by carefully observing the vampire traits, we can identify the grounds for medical and scientific explanations. The legend is associated with a number of genetic abnormalities, nutritional deficiency or virus infections that can cause behavioural changes. Historical facts changed over time and these distortions became the increasingly romantic and seductive image of the vampire.