Rabies: A compelling reason your parents said not to pet wild animals
Rabies is a group of viruses found around the world that produces a horrible set of symptoms in its victims before killing them. Appropriately, it came up when talking about vampire bats, and while my kindergartner tried to stay cool when first learning of a fatal, transmittable disease, it was clear that a little more information on the topic would be helpful. It’s hard to make this disease sound anything close to pleasant, of course, but more understanding seems better than not. And then there’s also the fact that rabies does some weird stuff, so there’s plenty to talk about.
The virus is transmitted from an infected animal to a new victim through contact with saliva, usually from a bite. In some places, dogs are a likely carrier, but in the US and other countries with vaccination requirements for animals, those bites are most likely to come from bats. The initial bite location may experience tingling or pain near the wound, but if left untreated by a doctor, the virus will move from the bite towards the brain where the symptoms can quickly spiral out of control.
Hijacking the body to increase chances of further transmission
As the virus progresses through the body, it can trigger a number of unusual reactions. One of the most famous is excessive salivation, which is the source of the idea of “foaming at the mouth.” This is thanks to the virus taking over the salivary glands and triggering excess production in order to facilitate further transmission to new hosts. At the same time, even considering drinking water to wash some of the saliva down or stay hydrated can trigger painful spasms in the throat and larynx. So while the virus maximizes its chances at transmission, the host may display an irrational fear of water, which is how rabies earned its original name of ‘hydrophobia.’
Additionally, to further increase the odds of transmission, infected animals will often behave aggressively and erratically. They may be much more prone to biting than normal, which is why it’s best to avoid any animal you may suspect is infected. While this reaction is common, a smaller percentage of infected animals experience the opposite pattern, becoming weak and immobile.
Eventually, an untreated host can suffer from a range of neurological issues, including hallucinations, terror, delirium, and paralysis. Death most often results from paralysis of the respiratory system, anywhere from 2 to 10 days after the first visible symptoms.
Stopping rabies before it gets started
So why aren’t we operating in constant terror of every dog, squirrel, raccoon and bat on a daily basis to avoid this grisly fate? We should be, to a degree— it’s never a good idea to handle an unknown animal, especially a mammal that may be infected. But many countries have also made great progress in reducing rabies infections with mandatory vaccination of animals like dogs, cats and livestock. Humans at risk for infection are often given a vaccination as treatment as well, ideally immediately after the bite occurs and before the virus has a chance to spread through the body.
Buying the immune system time by powering down the brain
In cases where treatment is delayed, more extreme therapies have been attempted. The most dramatic is the Milwaukee protocol, first attempted in 2004. A 15-year-old was bitten by a bat, but a proper diagnosis recognizing the rabies virus wasn’t given until 37 days later. She was then put into a medically-induced coma to limit her brain activity, as the virus rarely damages the brain directly, leaving the dysfunction of the brain to harm the patient. The hope was then that by preventing the brain from wreaking further havoc, the immune system would have more time to respond to the virus, with some help from other antiviral drugs along the way.
After six days, the patient was brought out the coma, and is generally healthy at this point. However, some damage to the brain did occur, and many functions and tasks, such as walking and running, have either been impaired or at least relearned.
The Milwaukee protocol has been used again since then with some amendments, and some success. Combined with prevention and caution, the United States now only reports one or two cases of human rabies per year. So don’t play with unknown fuzzy friends and we’ll keep that number nice and low.
Source: Rabies, Wikipedia