Rabies, a member of the lyssavirus family [lyssa = rage] of viruses, kills over 50,000 people worldwide annually. Transmission to humans typically comes from an infected animal like a dog, raccoon, or fox, and death was very common before recent protocols were developed (post-exposure prophylaxis). The virus is neurotropic, which means it has an affinity for nerve tissue, and moves quickly from infecting the body broadly to destroying the brain.