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Friday, 24 July 2015

On being rabid

Rabid dog, Middle Ages, Wikimedia

We get this word from the Latin rabidus, from rabere, to be mad. This word also gave us rabies, first used in 1661, according to the OED, and used to indicate an animal suffering from what was otherwise called canine madness or hydrophobia.

The disease itself was known in ancient Mesopotamia, where in 3000 BC, the city of Eshnuna had a law, setting out the punishment for a person who allowed a mad dog to escape and bite somebody. Rabies is peculiar, because most diseases, after 5000 years, are much less harmful, but rabies seems to manage without changing.

The cause of rabies is a small RNA virus, with just five genes. Once inside the body, it inserts its genes and a small amount of protein into a nerve cell. Then it works its way along, travelling toward the brain at about a centimetre each day, and crossing from nerve cell to nerve cell. Once it reaches the brain, the virus reproduces and spreads.

When viruses reach the salivary glands, they reproduce to make millions of new viral particles, and this is the point at which the victim becomes "mad", often biting and infecting other people, passing on the virus-rich saliva. Once it is inside the nerve cells, the attacking virus is safe from the vaccines, and the only other control is to amputate the bitten limb, cutting off the virus' route to the brain as the limb is cut off.

In France, rabies is called La Rage, but it actually produces two reactions among foxes: one of rage, when they become vicious and bite, but other foxes go all cuddly, licking their den-mates — but in either case, the infected fox is secreting rabies virus in its saliva, and infecting those around it, whether by biting or licking. The name "hydrophobia" reminds us that the victims feel painful spasms when they try to drink, and in their delirium, become terrified of water. 

It is quite possible that Edgar Allan Poe, master of the Gothic, died of rabies, although doctors at the time believed he was drunk. One of the key observations is that after he was found unconscious and taken to hospital, he had trouble drinking water.

Poe had a history of alcohol and opiate abuse, but according to his family, he had been 'clean' in the six months before his death, and while doctors thought he was suffering delirium tremens and offered him alcohol, he refused that as well. He went through several bouts of improvement and relapse, which is typical of a death by rabies in a human.

Poe loved cats, and may have contracted rabies from one. A 1994 case of a rabid kitten in New Hampshire led to medical costs of $1.1 million as 655 possible human contacts were treated. In other parts of the world, though, bats spread rabies, rather than kittens, foxes, wolves or dogs, and in France, before BSE, a vache enragée was a rabid cow, not a mad cow.

The fact that bats may spread rabies made one Spanish neurologist suggest that the vampire legend may come from a rabies epidemic in the Balkans and Hungary from 1721 to 1728. Juan Gómez-Alonso was watching a Dracula film when he noted some obvious similarities between vampires and what happens in rabies, such as aggressiveness and hypersexuality.

By that time, the vampire bats of South America would have been well-known, but it is open to question what came first: in the linkage between bats and vampirism.  A look at the often flaky and inexact Google ngram viewer reveals  "vampire bat" made its first appearance in 1796: more research is needed here!

Seven times as many men as women get rabies, and most vampires are male. About a quarter of all rabid men attempt to bite others, and rabid men often react to stimuli such as smells, water, and light with spasms of the facial and vocal muscles that can cause hoarse sounds, bared teeth and frothing at the mouth of bloody fluid — which may explain the use of garlic against vampires.

Gómez-Alonso points out that rabies acts on the brain to interfere with both sleep cycles and sexual behaviour: there are reports of some "rabid patients who practiced intercourse up to 30 times in a day", he wrote.

The vampire's fatal kiss may well reflect the presence of the virus in saliva and other bodily secretions, and vampires are supposed to come out at night, as a rabid person may well do. The association of bats and werewolves with vampirism would then be an obvious consequence of the part bats and wolves play in spreading rabies. Now what would Mr. Poe-the-horror-writer have done with that?

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