Rabies (cont.)

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How soon after an exposure should a person seek medical attention?

Urgency is the key to the timing of obtaining medical attention; if the bite is not serious (for example, little or no bleeding or tissue disruption), the individual should have the wound washed with soap and water (or antiseptic solution) as soon as possible. In addition, animal-control authorities need to be contacted and given as much information about the animal as is possible (for example, the animal type, its description and behavior, its location, the circumstances that led to the bite, and any other information requested). This is important to do immediately as it may give the authorities a chance to capture the animal. This will allow authorities to observe and test the animal for rabies. Untrained people should not attempt to approach the animal or to try to capture any animal suspected of having rabies.

In general, most clinicians and researchers suggest the person bitten or exposed to rabies be seen and treated (see treatment section below) within about 12 hours of the exposure, but the quicker the better. However, there is some time span in which treatment may be delayed (but delay in treatment is not recommended). For example, people adequately treated (see treatment section below) within 48 hours in the U.S. have never developed a fatal case of rabies to date. Do not worry about timing for stitches. Stitches are not usually recommended for bites as the stitches may help provide an environment for some bacteria found in saliva to proliferate. However, this may be modified if there is extensive tissue disruption; such patients need to be seen immediately.

How is a rabies infection diagnosed?

Usually, after a history of an animal bite or saliva exposure, the following questions may be asked:

  • Was the bite from an animal species that is susceptible to rabies (rats, mice, hamsters, and gerbils are rarely infected with rabies)? Wild animal bites, especially from skunks or raccoons, are always suspected to have rabies.
  • If a domestic animal was involved, was it acting strangely (see above)?
  • Was the animal vaccinated against rabies (most domesticated animals are)?
  • If the exposure was from saliva, was it near an open scratch, wound, or mucous membrane such as the mouth, nose, or eyes of the individual?
  • Is rabies known to be present in the area where the person was exposed?

Answers to these questions will help the clinician decide, usually in consultation with public-health officials, if the person has been presumptively exposed or infected with the rabies virus. In addition, the animal, if caught can be observed for signs of rabies or killed and the brain (and other tissue) can be examined by an immunofluorescence test for rabies virus. If these tests are positive, the patient is presumptively assumed to have been exposed to rabies. Treatment decisions are begun based on these findings (see treatment section below) because early treatment (up to about 48 hours post exposure) has been 100% effective in the U.S. according to several research sources.

Most people have rabies definitively diagnosed by an immunofluorescence test that confirms the presence or absence of rabies virus in tissue or saliva. These tests are usually done on people who develop the severe symptoms of rabies; they are not done on people who undergo appropriate treatment within 48 hours of exposure. Immunofluorescence tests can be performed on saliva, serum, spinal fluid, and skin biopsies of hair follicles at the nape of the neck. In addition, saliva can be tested by virus isolation or reverse transcription followed by polymerase chain reaction (RT-PCR). Serum and spinal fluid can also be tested for antibodies to rabies virus. Skin biopsy specimens can also be examined for rabies antigen in the cutaneous nerves at the base of hair follicles. Most labs suggest that at least two positive tests from different body areas are required for a definitive diagnosis. The vast majority of patients with a definitive diagnosis will die from the disease. However, these tests are useful because they can help differentiate rabies from other diseases that cause neurologic symptoms (for example, tetanus, viral encephalitis causes, smallpox, chickenpox, poliomyelitis, or other diseases).

Medically Reviewed by a Doctor on 4/18/2012

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Rabies - Symptoms Question: Did you or someone you know have rabies? What were the main symptoms and when did they appear?
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Rabies - Vaccine for Prevention Question: Has your pet received a rabies vaccine? Please share reasons for or against vaccinating your pet for this disease.

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