Rabies is a viral disease that is spread most often from the bite of a rabid animal to another animal or to a human.
The rabies virus affects the central nervous system including the brain and spinal cord of humans and animals. During the incubation period, the time between exposure to the virus and the appearance of symptoms, the virus travels along nerves towards the brain. This process takes an average of one to three months, but can range from several days to several years after exposure. The infection causes inflammation of the brain and spinal cord that can lead to encephalopathy and later, death. Encephalopathy is any type of disease that changes the brain's function or structure.
The rabies virus has two forms that cause different behaviours in affected animals. The forms of the disease are called furious and paralytic (dumb). If an animal has the furious form of rabies, it is easily provoked, distressed, and aggressive. Some wild animals may do things that are uncharacteristic for their species when infected with the furious form of the virus. For example, bats may come out during the day, or a wild animal may be friendlier than normal towards humans. With the paralytic form of rabies, some or all of the animal's body is paralyzed.