The 19th-century French chemist and microbiologist Louis Pasteur was prolific in his discoveries, but today, 119 years after he died at age 72, he is remembered primarily for a handful. Pasteur invented the food preservation process that bears his name. He is responsible for discoveries, such as the nature of bacteria, that established the field of microbiology; he was among the first scientists to apply that understanding to the question of how diseases are transmitted. And it was Louis Pasteur who developed the first vaccine for rabies, a usually fatal viral disease that causes inflammation in the brain.
Rabies is transmitted from animals to humans—and from animals to other animals—through saliva, which is mostly passed through bites. When an animal with rabies bites another animal, the virus is transmitted. One of the effects of rabies is a tendency to violence, including biting. Although dogs are both the prototypical vector and the most common worldwide, in the Americas, bat bites are actually more often the culprit. However, any small mammal could be carrying rabies. There are about 7,000 cases a year in the United States.
Prevention is best effective at the source, but often the animals that transmit the disease are feral if not actually wild, which presents an obstacle to finding and vaccinating all animals that could potentially spread rabies. That is why people are advised to avoid wild or feral animals when possible, and admire them from a distance. Even strays can be dangerous if they’ve been stray for a significant amount of time.
The reason there is such a focus on prevention is because there is no cure; if the disease is allowed to develop, it is almost certainly fatal. Fortunately, there is a certain amount of lag time between the bite and the disease taking hold during which measures can be taken that may save the patient’s life. Post-exposure prophylaxis can be used to try to ensure the disease never comes to pass. This involves cleaning the wound and administering rabies vaccine as soon as possible.
If symptoms do appear, there is still a slim possibility of saving the patient. A procedure called the Milwaukee Protocol, after the city where it was created, has been used with limited success, though the six patients who recovered since the procedure was created in 2004 is more than had recovered from rabies in all of human history until then. It involves anti-viral drugs administered to a patient in an induced coma.