The most common way for a dog to contract rabies is by being bitten by an infected animal. Rabid animals have the virus in their saliva. The infected saliva is also able to enter a dog's system through contact with mucous membranes or an open wound.
Wild mammals, especially bats, raccoons, skunks and foxes, are most likely to pass along the rabies virus. The disease typically attacks an animal's brain and central nervous system. Symptoms usually take two to eight weeks to show up after infection.
Early symptoms include behavioral changes, such as aggression or passivity. Eventually, dogs with rabies display extreme sensitivity to environmental stimulation, such as light, sound and touch. Their throat and jaw muscles become paralyzed. Paralysis of the hind legs leads to difficulty walking. Dogs often experience seizures before death occurs. There is no cure.