Rabies Incubation Period
The rabies incubation period is the length of time between infection with the rabies virus and the onset of symptoms. While the incubation period for rabies may vary from a few days to several years, it usually lasts one to three months. During the rabies incubation period, a bite from the infected animal does not carry a risk of rabies because the virus is not yet in the saliva.
The rabies virus enters the body through the saliva of an infected animal, usually as the result of a bite. In rare cases, the rabies virus can also be transmitted if infected saliva gets into an open wound or splashes into mucous membranes, such as those in the eyes, nose, or mouth (see Rabies Transmission).
When an animal is infected with the rabies virus, the virus multiplies within the body. Eventually, the virus cause rabies symptoms to develop. The period from the time from infection to the onset of symptoms is known as the rabies incubation period.
The rabies incubation period may vary from a few days to several years, but is typically one to three months. During this time, the rabies virus is multiplying within the body.
At some point, the rabies virus will travel along nerve cells to the brain. It multiplies in the brain very quickly, causing the end of the rabies incubation period, and the beginning of rabies symptoms. Usually within three to five days, the rabies virus has caused enough damage to the brain that the animal will begin to show unmistakable signs of rabies.
During the rabies incubation period, a bite by the infected animal does not carry a risk of rabies because the virus is not yet in the saliva. Only late in the disease, after the rabies virus has reached the brain and multiplied there to cause encephalitis (inflammation of the brain), does the virus move from the brain to the salivary glands and saliva.