Rabies. Just the word alone evokes a sense of fear and unease, and for good reason. Rabies is a viral disease that affects the brain and spinal cord of mammals-including humans. Typically transmitted through a bite from saliva entering the bloodstream, the virus travels from the bite site up through the nervous system to the spinal cord and eventually to the brain, where it causes severe swelling. The virus then travels to the salivary glands, filling the newly infected host with viral saliva. Symptoms of rabies can vary greatly - from passive and lethargic to violent and out of control. The prognosis for people and animals infected with rabies is death.