October 20, 2012 9:26:25 AM
We have viruses that we are rightly worried about; no one really knows what the next flu is going to be like, and who knows when some virus as bad as Ebola but spread as easily as a common cold is going to decimate the world's population. In America and most developing countries, though, we don't worry much about rabies. You've probably never seen a case or had a relative with the disease, but it is still in our thoughts if we see a raccoon in the backyard or a strange dog coming down the road. Rabies may no longer actively be with us, but it left a legacy of fear, and it is still a scary illness in much of the world. In Rabid: A Cultural History of the World's Most Diabolical Virus (Viking), Bill Wasik and Monica Murphy tell us why rabies never left our worry centers, even though, say, polio has. Even if we were to eradicate it as fully as we have smallpox, rabies has left us with ineradicable and nightmarish recollections of a horrible illness. The authors (he is a senior editor at Wired and she has degrees in public health and veterinary medicine, and they are married), in a readable and comprehensive account of the disease, show how it retains its fearful hold on us.
The authors warn that if you are squeamish, the book is not for you. Rabies is caused by a teensy virus, not much different from all the other viruses you might catch, except this one produces horrific symptoms. It is always spread by bites; until the apocalyptic day when it transforms into an aerosol- or mosquito-spread disease, if a mammal doesn't bite you, you can't get it. Rabies doesn't infect the bite, which if it is by a bat during sleep might not even be noticed by the victim. It does not run through the bloodstream, which would make it prey to the immune system. Instead, it creeps up a couple of centimeters every day along and inside of the nerves, up until it finally gets to its target, the brain, whereupon it sends a person back into a blighted animal existence. There may be fever, nausea, and vomiting at first, and then perhaps seizures in which the victim may snap or bite. There is a bizarre fear of water, not just of swallowing it, but of being in it, or even hearing it called by name. Control systems break down, and men can get involuntary erections and even hourly orgasms. Even more fiendishly, the symptoms go away for a while and the victims return to an intermittent lucidity to contemplate what they have done and what they are coming to, which is paralysis and death. Rabies not only has all these distressing symptoms, it is the most fatal virus in the world, killing almost every creature it infects. It is so fearful an illness that when Pasteur and his assistants were having to handle rabid dogs to do their research, a loaded revolver was always at hand, so that if any of them were bitten he could die quickly before the illness took hold.
The illness makes animals wilder, too. You expect bobcats to be wild, but the one with rabies is violently and intrusively aggressive. You expect otters and beavers to be mild, but not only do these meek creatures no longer shun human approach when rabid, they completely change characters and become avid, tenacious attackers. Even lambs can become demons. We are most familiar with rabies in mad dogs; everyone remembers Old Yeller but there is To Kill a Mockingbird, too. This is because dogs are our constant companions, even in societies that have no tradition of keeping them as pets. "Rabies coevolved to live in the dog," write the authors, "and the dog coevolved to live with us - and this confluence, the three of us, is far too combustible a thing." Part of the attraction of dogs is that they do have some wild animal left in them; once they get rabies, however, they are fully wild. Before vaccines there was nothing that could be done to control rabies in dogs except to shoot the dogs, sometimes indiscriminately. We are still doing this. Bali was an island free of rabies until one sailor brought a rabid dog there in 2008. The government was slow to react, and when it did, it targeted dogs, not the virus. Something over 100,000 dogs were killed, many shot in the streets; even so, several hundred people were killed by the virus before the strategy was changed to vaccination, which really is effective. (Is it too much to ask that anti-vaccine campaigners learn from this lesson?)
In this history of the disease are many attempts at cures; steam baths were supposed to help, or the application of brine pickles to the wound, or even a Chinese cure that called for killing the dog that made the bite, removing its brain, and rubbing that on the wound. In nineteenth century France, people worried that a friendly hearth dog could suddenly become rabid and bite, or simply lick, its owner and thereby inflict the disease. The remedy came from their countryman's discovery of a vaccine in 1885. Louis Pasteur didn't have a sure thing. He and his helpers were able to collect an infected dog's saliva (with that revolver at the ready), and transfer the infective agent from one animal to another. He was hoping to make the agent weaker, but it got stronger. Eventually, they hit upon a brilliant way of making the virus weaker by infecting rabbits, harvesting their spinal cords that contained the virus, and aging the spinal cords to attenuate the virus's potency. It was quickly clear that the vaccine worked; people with dog bites rushed to Pasteur's lab to get inoculated, and Pasteur's career took of with the launch of the Institut Pasteur.
Those who don't get the vaccine in time die. It's almost always true, but not quite. A few have survived with heroic treatments, but any standard protocol has yet to be agreed upon, partially because there are not many attempts at cures. The cures that have been effected have left patients alive but with neurological systems that are damaged. There are about 50,000 people who die of rabies every year, most in the developing world where few victims could ever get any sort of intensive treatment. Mass vaccination of dogs is the cost-effective way of dealing with the disease.
Someday we might look at rabies as a blessing. The virus has by evolutionary means solved the problem of getting directly into the central nervous system (bypassing the famous "blood brain barrier") in a way that doctors now wish could be the same direct route for medicines that would have their effect in the brain. Researchers have learned which peptide allows the virus to get into the neurons; the idea is that if you want to get a medicine directly into the brain, hitch it to the rabies-derived peptide. It may well be that anti-encephalitis or anti-Alzheimer's medicines are delivered this way in the future. The authors conclude this harrowing book with the optimistic note that we have the potential to take rabies's lethal tactic and effect brand new types of cures. Before the conclusion, however, they have examined not just the pathology and epidemiology of the disease, but also the lore developed from it. Without rabies, we probably would not have a tradition of horror books and movies based on vampires, werewolves, and zombies. Even if the rabies virus were wiped out, the disease would still be around to scare us out of our wits.