The viral infection known as rabies or hydrophobia affects the brain and the spinal cord. Rabies kills over 50,000 people around the world each year. The virus comes from the rhabdovirus group, a family of bullet-shaped viruses. Transmission occurs mainly through the saliva of an infected mammal, but the Centers for Disease Control and Prevention (CDC) mentions that contact with infected brain tissue or nervous system tissue can also cause infections.
Bites
Bites from infected animals cause most rabies infections. When the saliva of the animal carrying the infection enters the body, the virus moves into the nerves from the site of the bite. It then travels through the nerves and enters the spinal cord and proceeds, finally, to the brain. If the animal bites a person in the face, the virus travels more directly to the brain stem. Bites from infected dogs cause most human rabies infections in Africa, Asia and Latin America, while bats cause most of the infections in the United States.
Skin Abrasions
The rabies virus can be transmitted if the saliva of a virus-carrying animal comes into contact with broken skin, such as a scratch or an open wound. The virus cannot penetrate any intact or undamaged skin. The World Health Organization (WHO) mentions that rabies transmission can occur even if certain species of infected animals merely lick a person or another animal on an area with abraded skin. Infection can thus happen without any bite. Some species of animals can become infected by rabies, but remain only victims of the disease and do not transmit it.
Mucous membranes
The mucous membranes, or mucosa, are thin layers of tissue that line all the body passages that come into contact with the exterior. The membranes remain wet because of the mucous on their surface. Rabies infection can occur through contact between the saliva of an infected animal and the mucous membranes of, for example, the eyes, the inside of the eyelids and the nose or the mouth
Transplants
According to the Centers for Control and Prevention, an organ transplanted from an infected donor can cause the rabies infection in the recipient.
Airborne Droplets
Merck Manual mentions that in certain places such as caves inhabited by infected bats, rabies transmission may occur via the inhalation of virus-containing airborne droplets.
