What Causes Rabies?

Rabies is caused by a virus that can infect humans, pets, and wildlife.2,3

The rabies virus is typically found in the saliva of rabid animals. A person can become infected when an animal with rabies bites them deep enough to let the virus get beneath their skin. It is also possible for rabies to be transmitted in other ways, like when a rabid animal's saliva or brain tissue comes in contact with a fresh, open scratch wound or when it touches a person’s eyes, nose, or mouth.2

What Are the Symptoms of Rabies?

The word “rabies” comes from a Latin term meaning fury or rage. Most of the time, rabies causes agitation, confusion, and seizures—the fury for which it was named. However, in 20% of cases, rabies progresses more slowly, causing paralysis starting at the wound site.1,4,5

Depending on which strain of virus it is and how close it is to the central nervous system when it enters the body, the disease could take hold in as little as 5 days.6

Early signs of rabies may seem like the flu. These symptoms include7:

  • General discomfort
  • Headaches
  • Persistent fever

As the disease continues to attack the nervous system, other symptoms appear, including 8:

  • Irritability and aggressiveness
  • Bizarre thoughts or hallucinations
  • Extreme sensitivity to light and sound
  • Muscle spasms

Foaming at the mouth, which has long been associated with rabies, is caused by an overproduction of saliva (known as hypersalivation) and muscle spasms in the throat.3,8 Eventually, the rabies virus causes a severe swelling of the brain (encephalitis). Death usually results 7-10 days after the first signs of the disease.5,6

Is There a Cure for Rabies?

NO. There is no recognized medical treatment. Once the signs and symptoms appear, the disease is almost always fatal.2

Can Rabies Be Prevented?

YES. Rabies is preventable—but only with proper protective (prophylactic) measures. Failing to get protection after being exposed to the rabies virus could cost you your life.2,6,9

Discover the Protection of Postexposure Prophylaxis for Rabies

The Danger of Ignoring Rabies Exposure

In 2021 there were 5 human fatalities due to rabies in the US—the highest number in decades. Here are a few other cases of preventable deaths attributed to the rabies virus.10


In mid-August of 2021, an 80-year-old Illinois man awoke to find a bat on his neck. The bat was captured and determined to be positive for rabies. Health officials advised the man to start postexposure treatment for rabies immediately. He declined. Early in September, the man reported neck pain, headache, difficulty controlling his arms, finger numbness, and difficulty speaking. He died days later, with the Centers for Disease Control and Prevention confirming the diagnosis of rabies.11


In January 2018, a 6-year-old boy from Florida was bitten by a bat. Approximately 2 weeks later, he developed symptoms and later died of rabies.12


A second case in 2018 involved a 69-year-old woman from Delaware who died from rabies in August 2018.12


In November 2018, a 55-year-old man from Utah died from a rabies infection. He started having symptoms, but attributed it to a work accident, and was hospitalized. He received supportive medical care, but died about 2 weeks later. A postmortem examination confirmed he died of rabies. Although no bite was reported, his family stated that he had removed bats from his house without gloves and never received PEP for any exposures.12


Two human rabies cases were reported in 2017. The first case was a woman who had traveled to India where she was bitten by a dog in March but did not receive PEP. In May of that year, she developed right-arm tingling followed by shortness of breath, anxiety, and trouble swallowing. She died in the same month.13


The second case in 2017 involved a woman bitten on her right hand by a bat in August. She did not seek medical care until she developed a fever and pain in her right arm and neck in October. She died 4 days later.13

Seek Medical Attention for Any Suspicion of Exposure to Rabies

Find Out Which Animals Are Most Likely to Carry Rabies

Important Safety Information for HyperRAB® (rabies immune globulin [human])

Indication and Usage
HYPERRAB® (rabies immune globulin [human]) is indicated for postexposure prophylaxis, along with rabies vaccine, for all persons suspected of exposure to rabies.

Limitations of Use
Persons who have been previously immunized with rabies vaccine and have a confirmed adequate rabies antibody titer should receive only vaccine. For unvaccinated persons, the combination of HYPERRAB and vaccine is recommended for both bite and nonbite exposures regardless of the time interval between exposure and initiation of postexposure prophylaxis. Beyond 7 days (after the first vaccine dose), HYPERRAB is not indicated since an antibody response to vaccine is presumed to have occurred.

Important Safety Information

For infiltration and intramuscular use only.

Severe hypersensitivity reactions may occur with HYPERRAB. Patients with a history of prior systemic allergic reactions to human immunoglobulin preparations are at a greater risk of developing severe hypersensitivity and anaphylactic reactions. Have epinephrine available for treatment of acute allergic symptoms, should they occur.

HYPERRAB is made from human blood and may carry a risk of transmitting infectious agents, eg, viruses, the variant Creutzfeldt-Jakob disease (vCJD) agent, and, theoretically, the Creutzfeldt-Jakob disease (CJD) agent.

The most common adverse reactions in >5% of subjects during clinical trials were injection-site pain, headache, injection-site nodule, abdominal pain, diarrhea, flatulence, nasal congestion, and oropharyngeal pain.

Do not administer repeated doses of HYPERRAB once vaccine treatment has been initiated as this could prevent the full expression of active immunity expected from the rabies vaccine.

Other antibodies in the HYPERRAB preparation may interfere with the response to live vaccines such as measles, mumps, polio, or rubella. Defer immunization with live vaccines for 4 months after HYPERRAB administration.

Please see full Prescribing Information for HYPERRAB.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088


  1. Feder H, Petersen B, Robertson K, et al. Rabies: still a uniformly fatal disease? Historical occurrence, epidemiological trends, and paradigm shifts. Curr Infect Dis Rep. 2012;14:408–422.
  2. Manning SE, Rupprecht CE, Fishbein D, et al. Human rabies prevention—United States, 2008: recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep. 2008;57(RR-3):1-28.
  3. American Humane. Rabies facts & prevention tips. Updated August 25, 2016. Accessed March 13, 2022. https://www.americanhumane.org/fact-sheet/rabies-facts-prevention-tips.
  4. World Health Organization (WHO). Rabies. WHO website. Accessed March 12, 2022. https://www.who.int/news-room/fact-sheets/detail/rabies.
  5. Crowcroft NS, Thampi N. The prevention and management of rabies. BMJ. 2015;350:g7827.
  6. Kaur M, Garg R, Singh S, Bhatnagar R. Rabies vaccines: where do we stand, where are we heading? Expert Rev Vaccines. 2015;14(3):369-381.
  7. Centers for Disease Control and Prevention (CDC). What are the signs and symptoms of rabies? Updated December 23, 2021. Accessed March 19, 2022. https://www.cdc.gov/rabies/symptoms.
  8. What is rabies? Nemours Kid Health. Updated February 2019. Accessed April 7, 2022. https://kidshealth.org/en/parents/rabies.html.
  9. Nigg AJ, Walker PL. Overview, prevention, and treatment of rabies. Pharmacotherapy. 2009;29(10):1182-1195.
  10. Gross J. U.S. records 5 rabies deaths in 2021, highest number in a decade. The New York Times. https://www.nytimes.com/2022/01/07/health/rabies-deaths.html.
  11. Heching D. Ill man who denied treatment dies of rabies after bat colony was found in his home. People.com. Published September 28, 2021. Accessed April 7, 2022. https://people.com/health/illinois-man-dies-of-rabies-after-denying-treatment.
  12. Ma X, Monroe B, Cleaton J, et al. Rabies surveillance in the United States during 2018. J Am Vet Med Assoc. 2020;256:195–208.
  13. Ma X, Monroe B, Cleaton J, et al. Rabies surveillance in the United States during 2017. J Am Vet Med Assoc. 2018;253:1555–1568.
  14. Ma X, Monroe B, Cleaton J, et al. Rabies surveillance in the United States during 2016. J Am Vet Med Assoc. 2018;252:945-957.