Rabies Overview

Rabies is a preventable viral disease of mammals most often transmitted through the bite of a rabid animal. The vast majority of rabies cases reported to the Centers for Disease Control and Prevention (CDC) each year occur in wild animals like raccoons, skunks, bats, and foxes. Domestic animals account for less than 10% of the reported rabies cases, with cats, cattle, and dogs most often reported rabid.

Rabies virus infects the central nervous system, causing encephalopathy and ultimately death. Early symptoms of rabies in humans are nonspecific, consisting of fever, headache, and general malaise.

As the disease progresses, neurological symptoms appear and may include insomnia, anxiety, confusion, slight or partial paralysis, excitation, hallucinations, agitation, hypersalivation, difficulty swallowing, and hydrophobia (fear of water). Death usually occurs within days of the onset of symptoms.

Several tests are necessary to diagnose rabies before death in humans; no single test is sufficient. Tests are performed on samples of saliva, serum, spinal fluid, and skin biopsies of hair follicles at the nape of the neck. Saliva can be tested by virus isolation or reverse transcription followed by polymerase chain reaction (RT-PCR). Serum and spinal fluid are tested for antibodies to rabies virus. Skin biopsy specimens are examined for rabies antigen in the cutaneous nerves at the base of hair follicles.

Rabies is a medical urgency not an emergency, but decisions must not be delayed. Any wounds should be immediately washed and medical attention from a health care professional should be sought for any trauma due to an animal attack before considering the need for rabies vaccination.

The need for rabies vaccination should be evaluated under the advisement of your physician and/or a state or local health department official. Decisions to start vaccination, known as postexposure prophylaxis (PEP), will be based on your type of exposure, the animal you were exposed to, as well as laboratory and surveillance information for the area where the exposure occurred.

Source: CDC