Back

Rabies

Definition

Rabies is an infection that affects the brain and spine. Rabies is almost always fatal unless treated before symptoms appear.
The Nervous System
Nucleus factsheet image
© 2011 Nucleus Medical Media, Inc.

Causes

Rabies is caused by a virus. It is found in infected, warm-blooded animals. Animals that commonly carry the virus include:
The virus is in the saliva, brain, or nerve tissue of infected animals. Humans most often contract rabies through a bite or scratch from an infected animal. The virus may also be passed if infected tissue comes into contact with skin in the eyes, nose, or mouth.

Risk Factors

The only risk factor is contact with an infected animal.
In most parts of the United States, any contact with a bat may be considered a rabies risk factor. Seek medical advice if you find a bat anywhere inside your home.

Symptoms

Symptoms often start within 3-7 weeks. In some cases, the virus can incubate up to 1 or more years. Death usually occurs within a week after symptoms appear.
Symptoms in humans may include:

Diagnosis

If you think you have been exposed to rabies, see a doctor or contact a public health official right away.
If the animal is available and appears well, it will be kept under observation to monitor its health. If no symptoms develop, you are not at risk for rabies. If the animal is sick or dead, it may be examined for the presence of the virus. In the meantime, you may be advised to begin treatment.
If the animal is unavailable, treatment may be given. The decision to give treatment maybe based on factors such as:

Treatment

If an animal has bitten you, immediately do the following:
If it is likely that you have been exposed to rabies, your doctor will recommend postexposure prophylaxis. This is treatment to prevent illness from developing. This treatment involves 2 injections:

Human Rabies Immune Globulin (HRIG)

This is given within 24 hours after exposure. It contains large amounts of antibodies to inactivate or destroy the rabies virus. In most cases, half of the dose is injected into the wound and surrounding tissue. The rest is given into a muscle. If you have previously received the rabies vaccine, you may not need the HRIG shot.

Rabies Vaccines

Rabies vaccines make your immune system create antibodies against the virus. These antibodies will live in your body for many years. The vaccine is delivered in several shots over the next several weeks. The vaccine will be injected into your muscles.
There are several types of rabies vaccines available including the:
  • Human diploid cell vaccine (HDCV)
  • Purified chick embryo cell vaccine (PCECV)
Certain medication may interfere with your response to the rabies vaccine. Be sure to tell your doctor about all medications, herbs, or supplements that you take on a regular basis.

Prevention

To help prevent rabies:

RESOURCES

Centers for Disease Control and Prevention http://www.cdc.gov

National Institute of Allergy and Infectious Diseases http://www.niaid.nih.gov

CANADIAN RESOURCES

Health Canada http://www.hc-sc.gc.ca

Public Health Agency of Canada http://www.phac-aspc.gc.ca

References

Rabies. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/rabies. Updated September 24, 2013. Accessed January 13, 2015.

Rabies. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated October 13, 2014. Accessed January 13, 2015.

3/26/2010 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Use of a reduced (4-dose) vaccine schedule for postexposure prophylaxis to prevent human rabies. 2010;59(2):1.

Revision Information