Rabies (rabies, "madness, rage, fury") is a viral zoonotic neuroinvasive disease that causes acute encephalitis (inflammation of the brain) in mammals. In non-vaccinated humans, rabies is almost invariably fatal after neurological symptoms have developed, but prompt post-exposure vaccination may prevent the virus from progressing. There are only six known cases of a person surviving symptomatic rabies, and only one known case of survival in which the patient received no rabies-specific treatment either before or after illness onset.