Vampires are enjoying rather a lot of notoriety at present, but this isn’t exactly a new thing. I feel I am adequately qualified to discuss the genre having seen shed-loads of vampire films, from the good – Thomas Alfredson’s outstanding Let the Right One In; the enjoyable – Blade, Daybreakers, Night Watch; the bizarre – Chan-Wook Park’s Thirst, Guillermo del Toro’s Cronos; the vomit-worthy Twilight; and the just plain rubbish – Francis Ford Coppola’s Dracula and the live action shit-fest that was Blood The last Vampire.
On the small screen, there’s the trash-tastic True Blood and the outstanding Being Human. But I will always think fondly of Joss Whedon’s Buffy the Vampire Slayer.
All these different vampire streams carry their own internal logic when it covers who turns into a vampire – some contend you become a vampire when a vamp chooses you as a late night snack, others stick with the more invasive requirement of the victim imbibing vampire blood in order to become a vampire. There doesn’t seem to be much consensus on the matter. If you take Bram Stoker’s original work as gospel, if you are drunk from around three times, you become a vampire. This particular piece of canon doesn’t seem to have been picked up elsewhere (aside from Elizabeth Kostova’s book The Historian).
But do these make sense biologically? If you consider vampirism as a communicable disease, as it is described in both Daybreakers and Thirst, there must be an infectious agent that is transmitted to the victim. However, in the Twilight series, it is stated that vampirism is spread by venom. Since Twilight is beyond science (and anyone who isn’t a teenage girl), we shall consider the evidence uncovered by other films that look into the vampirism disease.
Vampirism as an infectious disease
If whatever causes vampirism is an infectious agent – like a bacteria or virus – it could lead to either a chronic infection or an acute infection. If it’s a chronic infection, the vampirism is either the body’s way of dealing with the virus or what the virus itself does to the body. If the infection is acute, and the immune system defeats the infection, it leaves the body in a ravaged, albeit immortal, state. All the films that go into scientific detail appear to describe a chronic infection that, in some cases, can theoretically be cured.
Depending on which canon you follow, if the bite itself spreads the vampirism disease, presumably the saliva contains the agent; this is the case in Underworld. Here, vampirism is spread by a virus, although most people who are bitten do not survive. Those that survive become vampires, but sadly, Selene (Kate Beckinsale) doesn’t go into this any further.
Fortunately for me, other films have scientists that have looked at vampirism properly. In Daybreakers, Edward Dalton (Ethan Hawke) is a haematologist working for a company looking for a blood substitute, in a world where the vampirism disease has spread to 95 % of the world’s population. The vampiric majority are facing a catastrophic blood shortage and humans are almost extinct. Vampires not being able to drink human blood become a sort of sub-vampire with deterioration of the frontal lobe, which leads to reduced brain function and loss of the ability to speak, as well as increased aggression and associated low levels of serotonin in the brain. There are actual studies that have linked low serotonin levels in the brain to increased aggression. While the infectious agent itself isn’t discussed in any particular detail, we know that it is passed on through a bite.
Notably, the protagonists come across a cure for vampirism, it doesn’t exactly make sense scientifically however. A vampire can be cured if they are briefly exposed to sunlight, but not for so long that they are burnt to a crisp. It seems to be a sort of cleansing of the blood; the heart begins to beat again, the circulation and immune system come back online. It seems to be almost like the heart is shocked back into life. But whatever cures the vampirism, this curative agent remains in the blood, as any vampire consuming the blood of a cured vampire also gets cured. This is somewhat reminiscent to an antibody-mediated effect; antibodies from the cured vampire fight off the infection when they enter the bloodstream of a vampire. This would not work in humans however, as the antibodies would be digested in the stomach. But then we have no idea of what vampire physiology is like.
Chan Wook-Park’s Thirst also describes vampirism in terms of a virus. Priest Sang-Hyan (Kang-Ho Song) volunteers for an experimental vaccine against a horrific virus. The virus causes extensive blistering, it spreads to the internal organs, and when the blisters burst, the sufferer dies of blood loss. If you look up viruses that cause blisters you get two results: chicken pox and herpes. In chicken pox, the virus does cause respiratory symptoms, but these tend to be mild. In rare cases, organs such as the liver and brain become infected and this can lead to death. Sang-Hyan receives a blood transfusion and, surprisingly, lives. However, he later relapses and dies, and returns as a vampire. He must consume human blood to stave off the symptoms of the disease. To pass on the infection, one must drink vampire blood. It’s unclear whether it is the virus itself that causes the vampirism or that possibly the donor blood Sang-Hyan receives while dying of the infection. I suspect it is the former rather than the latter. The disease itself seems to me more reminiscent of viral haemorrhagic fevers caused by Ebola or Dengue. Dengue starts off as a rash with aches and pains and can often be mild, in a few cases it progresses to excessive amounts of bleeding from the gut and lead to shock. Interestingly, Dengue is spread by mosquito bites; the mosquito drinks blood from an infected individual, the virus infects the mosquito’s salivary glands so that it transmits the disease when it feeds. Also, Dengue can be caught by receiving contaminated blood. This rather interestingly reflects the two different transmission methods of vampirism.
Blade is very much reliant on its haemotologst Karen Jensen (N’Bushe Wright). She takes smears of blood samples an looks at them under a microscope and describes the blood cells as being biconvex and not containing much haemoglobin (the protein that carries oxygen in the blood). In humans, red blood cells are biconcave, red blood cells in birds are biconvex – like a Smartie. The blood smear is described by the doctor as being like what you’d see in haemolytic anaemia. The vampires, including Blade (Wesley Snipes), a human-vampire hybrid, must drink human blood in order to maintain their haemoglobin levels. Jensen also describes the causative agent as a virus (even though it is referred to as a venom earlier in the film), which rewrites human DNA. This idea of a viruses re-writing DNA isn’t unheard of, scientists believe that rather a lot of human DNA came from viruses. She comes up with a cure that involves using gene therapy to return the vampire’s DNA to normal. Although scientists were able to treat sickle cell anaemias in mice in 2001 (three years after Blade’s release), successful trials using this technique are scarce, or more accurately, non-existent. Blade has fun with other jabs at science, like using the anticoagulant, sodium citrate, which forms an explosive combination with vampire blood. It also has garlic causing a severe allergic reaction in vampires.
Epidemiology of vampirism
How the vampirism spreads and the number of people it affects will vary vastly depending on the way it is transmitted. If everyone who is bitten becomes a vampire, you end up with the situation in Daybreakers where a vast vampire population is struggling to survive off blood from a diminishing human population. What we’d end up with is extinction of both species, presumably, this would be the end-point in Blade and Underworld as well as in Daybreakers. If people only turn when they are fed vampire blood, this would lead to much more sustainable vampire population growth – evolutionarily, this would make the most sense for the vampire virus. A virus that causes a disease with a high mortality rate which is easily spread will wipe out a large group of people very quickly, the virus would die along with the victims. This is evolutionarily bad for the virus.
Until we get epidemiologists and virologists working on vampire films, none of this will be clarified. But what really intrigues me is why wooden stakes, sunlight, holy water and crucifixes would affect vampires. Not that there’s any point applying logic to the spread of an imaginary virus…