Rabies affects mammals (including humans), attacking the brain and causing severe inflammation. Without treatment, it may be fatal. In nearly all cases of rabies, the virus that causes it is transmitted through the saliva of an infected animal, most often through a bite. When the rabies virus reaches the brain, it multiplies quickly and rabies symptoms begin. In humans, symptoms often begin with fever, headache, and fatigue, and are usually followed by confusion, agitation, hallucination, and paralysis.
Rabies is caused by a virus that attacks the brain, causing severe inflammation (encephalopathy) and death if not treated. This virus is called the rabies virus. The rabies virus, which is an RNA virus, is part of the family of viruses called Rhabdoviruses. It appears that there are several variations of the rabies virus that are able to cause rabies.
In nearly all cases of rabies, the virus enters the body through the saliva of an infected animal, usually by a bite, but it 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. From the saliva's point of entry, the rabies virus travels along nerve cells to the brain. It multiplies there and moves to the salivary glands. In a rabid animal, the cycle is repeated when the animal bites a person or another animal.
Although all species of mammals can become infected with the rabies virus, only a few species are best able to spread the virus to other animals. These species include, but are not limited to:
Only mammals get rabies. Birds, reptiles, amphibians, and fish do not get the disease.
(Click Animals With Rabies for more information.)