Rabies has been known since ancient times, and continues to produce thousands of deaths each year, primarily in Asia and Africa, almost invariably from the bite of an infected animal. There is usually at least a 2-3 week incubation period, while the virus is traveling up the nerves to the brain. This allows a period of time for a prophylactic vaccine treatment. Once symptoms actually develop, however, the disease is almost universally fatal.
Rabies is present as a Reservoir in wild animals. For this reason, flavorful baits laced with oral rabies vaccine are often sprinkled throughout endemic areas near human settlements, an expensive, although cost effective treatment. A bite from any wild animal is worrisome, but, in the United States, Bats are the main source of infection. The last fatal case of rabies in the United States occurred in an Illinois man who awakened with a bat on his neck. He refused Rabies vaccine and was dead within two weeks.
Dog bite used to be the most common source of rabies in America, but this is no longer the case, due to almost universal Rabies vaccination in American dogs. In India, however, the biggest problem is still dogs, which amazingly have recently been protected by law. India accounts for approximately 1/3 of the worlds rabies fatalities.
The development of rabies vaccine is an interesting story. It was first developed by Louis Pasteur and given in 1885 to a 12-year-old boy who had been mauled by a rabid dog.
The vaccine was prepared from the spinal cord of a rabbit who had the virus growing in his nervous system. Rabbits are very susceptible to rabies, and repeated rabbit passage increases the virulence of the virus. The virulence can be diminished by drying out infected tissue in the air, and Pasteur used a piece of spinal cord from an infected animal which was dried in the air for several days. The boy was given multiple doses of the vaccine over as many days, and survived. This technological achievement occurred before anybody even knew what a virus was. These invisible, infectious sources were called “filterable viruses”, since the infectious agent could not be strained out of the blood plasma by passing it through a filter which effectively removed bacteria, much larger entities.
The Rabies virus has been very clever over the millennia. It modifies the behavior of its victim towards irritability and aggression, which makes transmission of the virus more likely. It is highly concentrated in the salivary glands, increasing the likelihood that the aggressive animal’s bite will transmit the virus.
If you or an acquaintance are bitten under suspicious circumstances, be sure to get the vaccine, which is now been perfected and inactivated so that side effects are most acceptable, considering the almost universal fatality of the disease.