Rabies is caused by a virus found in infected, warm blooded animals. Animals that commonly carry the virus include:

  • Bats
  • Raccoons
  • Skunks
  • Foxes
  • Coyotes

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 US, any contact with a bat may be considered a rabies risk factor. People who find a bat inside their home should seek medical advice.



Symptoms often start within 3 to 7 weeks. In some people, the virus can incubate up to 1 or more years. Death usually occurs within a week after symptoms appear.

Symptoms in humans may include:

  • Pain, tingling, or itching at the site of the bite wound or other site of viral entry
  • Stiff muscles
  • Increased production of thick saliva
  • Flu like symptoms, such as headache, fever, fatigue, nausea
  • Painful spasms and contractions of the throat when exposed to water
  • Erratic, excited, or bizarre behavior
  • Paralysis


Anyone who may have been exposed to rabies should seek medical care right away.

If the animal is available and appears well, then it will be kept under observation to monitor its health. If no symptoms develop, then there is no risk for rabies. If the animal is sick or dead, then it may be tested to look for signs of the virus. Treatment may be given before test results on the animal are available.

If the animal is not available, then treatment may be given. The decision to give treatment may be based on factors such as the species of the animal and where the encounter took place.



People who have been bitten by an animal should wash the wound with soap and water and then get medical help right away.

A person who was likely exposed to rabies will need treatment. This involves two different types of 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 people, half of the dose is injected into the wound and surrounding tissue. The rest is given into a muscle. People who have gotten the rabies vaccine in the past may not need the HRIG shot.

Rabies Vaccines

Rabies vaccines make the immune system create antibodies against the virus. These antibodies will live in the body for many years. The vaccine is given in shots over the next several weeks. The vaccine will be injected into the muscles.


To lower the risk of rabies:

  • Vaccinate house pets.
  • Avoid contact with wild animals.
  • Do not touch any wild animal—even if it appears to be dead.
  • Seal basement, porch, and attic openings to prevent an animal from entering the home.
  • Report animals acting strange or appearing sick to local animal control.
  • People should get the rabies vaccine if they frequently come in contact with animals that may have rabies.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.