Rabies

Rabies is a viral disease affecting the central nervous system of humans and other animals. The virus is a lyssavirus, belonging to the family Rhabdoviridae. It is typically transmitted through bites or scratches from an infected animal, particularly dogs; the saliva of an infected animal introduces the virus into the nervous system.

Once symptoms of the brain disease appear, the disease is invariably fatal. However, there are preventive treatments available after exposure (post-exposure prophylaxis), given after a bite, which greatly reduce the likelihood of the disease developing if started promptly.

How the virus works

After entering muscle cells near the bite wound, the virus travels along nerve fibers to the spinal cord and brain. The incubation period between the bite and onset of symptoms is typically several weeks to several months, and can depend on where the bite is located—bites closer to the head may have a shorter incubation period.

Symptoms

Early symptoms include fever, headache, and pain or tingling at the bite site. Later, agitation, confusion, muscle spasms, and difficulty swallowing water develop—the latter known as hydrophobia (fear of water). There is also a form in which the body becomes progressively paralyzed, beginning with the bitten limb.

Prevention

The most important measure is vaccination of dogs, since they are the leading source of human infection. People whose work poses risk—such as veterinarians—are given preventive vaccine. After a bite, the wound is recommended to be washed with soap and water for an extended time, followed by vaccine and, if needed, immunoglobulin.