The infection is caused by rabies virus. Rabies is spread by infected saliva that enters the body through a bite or broken skin. The virus travels from the wound to the brain, where it causes swelling or inflammation. This inflammation leads to symptoms of the disease. Most rabies deaths occur in children.

In the past, human rabies cases in the United States usually resulted from a dog bite. Recently, more cases of human rabies have been linked to bats and raccoons. Dog bites are a common cause of rabies in developing countries, especially Asia and Africa. There have been no reports of rabies caused by dog bites in the United States for a number of years due to widespread animal vaccination.

Other wild animals that can spread the rabies virus include:

Foxes

Skunks

In rare cases, rabies has been transmitted without an actual bite. This type of infection is believed to be caused by infected saliva that has gotten into the air, usually in bat caves.