If you think the zombies that infest the Big Brother house in Dead Set are just products of Charlie Brooker's fevered imagination – well, that's just what the CIA wants you to think
Next week sees the airing of Dead Set, a five-part zombie thriller set in the Big Brother house and penned by Charlie Brooker. But there's more to zombies than fake blood and prosthetic peeling skin. Reanimation, mind control and zombifying parasites are more real and more terrifying than any horror film.
Zombies made their debut in the world's consciousness in 1889 via the pages of Harper's Magazine. A short article by amateur anthropologist Lafcadio Hearn reported stories of the corps cadavres – "the walking dead" – haunting the Caribbean nation of Haiti. Almost 100 years later, Harvard ethnobotanist Wade Davis travelled to Haiti to investigate. Writing about his experiences in The Serpent and the Rainbow, he claimed that tetrodotoxin, the poison of the deadly pufferfish, was the chemical agent responsible. Using this drug, a voodoo priest known as a houngan could induce a death-like state in a victim, from which the victim was then partially revived and made to live as a mindless slave. However, this doesn't match the known pharmacology of tetrodotoxin, and to date there's no hard evidence to support Davis's claim.
By the time Davis's book hit the shelves, the CIA had been engaged in its own zombie-creation scheme for over 30 years. The clandestine Project MKULTRA was created in 1953 to develop the CIA's interrogation, behaviour-modification and mind-control abilities. This involved dosing unsuspecting subjects with drugs such as temazepam, mescaline, psilocybin and Sodium Pentothal; more inventive techniques such as hypnosis, sub-aural frequency blasts, and sleep deprivation were also employed. When details of MKULTRA surfaced there was a public outcry; the programme was officially abandoned and all records ordered destroyed. Whether the CIA ever discovered the zombie formula remains unknown.
Soviet scientists had their own zombie-themed research, retold in the snappily-titled 1940s video Experiments in the Revival of Organisms. Although the veracity of the video is in question, the experiments it depicts – such as keeping a dog's severed head alive with artificial circulation – are in keeping with research of the time. This work would go one to inform procedures such as open-heart surgery and organ transplant, though Resident Evil-style zombie dogs were thankfully confined to the laboratory bench.
All this, however, pales in comparison to examples found in nature. Parasitic species outnumber the free-living a mighty four to one, and display high proficiency in infecting and enslaving their hosts. Take for instance the emerald cockroach wasp (Ampulex compressa). The female preys on cockroaches, driving her sting directly into the brain of the unfortunate insect. The venom destroys the roach's escape reflex; it is then buried alive along with a single wasp egg. Once hatched, the wasp larva burrows into its living host and devours it from the inside. Infamous serial killer Jeffrey Dahmer once attempted a similar feat, trepanning one of his victims and injecting acid into their brain to create a zombie, without success.
Another parasite, Toxoplasma gondii, infects rats and mice. In order to reach its final host, a cat, the protozoan reprograms the host's behaviour. The rat becomes bolder, losing its instinctual fear of cats. This foolhardy conduct ends up delivering it to the jaws of a passing cat, and the brain-warping parasite is passed on. T gondii will infect just about any warm-blooded animal, including humans, and recent research shows it can modify our behaviour too. Infected men become more suspicious, women become more outgoing. Infected drivers are more likely to be involved in a car crash. It's estimated that 40% of the world's human population is infected via cat faeces. T gondii. So if you really want to find a mind-altered zombie, the best place to start looking might be a mirror.