How Is the Rabies Virus Transmitted?

The rabies virus infects mammals. Any wound where the saliva of an infected animal penetrates the skin is a possible rabies exposure.1

Human hand with scratch and bite wounds from an animal that may have rabies.

Bite Wounds Are the Most Common Exposure to Rabies1

The rabies virus is present in the saliva of infected mammals. Transmission occurs when infected saliva penetrates the skin, making bite wounds from rabid animals the most common form of exposure. Although the risk of rabies exposure may increase with the severity of the wound, all animal wounds, no matter how minor, present a risk of exposure.1

A child's hands with scratch marks from a possibly rabid animal.

Animal Scratches and Nonbite Exposures

The contamination of an open wound or mucous membrane with saliva or other potentially infectious material from a rabid animal can constitute a nonbite exposure. Although nonbite wounds generally present a lower risk of exposure, there are reports of rabies transmission from scratches. Bat scratches are a particular concern because bat rabies virus can replicate in epithelial cells. These nonbite exposures suggest it’s still prudent to make an assessment to determine whether postexposure prophylaxis (PEP) is warranted.1,2

It’s important to remember nonbite exposures may include surgical recipients of corneas, solid organs, and vascular tissue transplanted from patients who died of rabies as well as individuals exposed to large amounts of aerosolized rabies virus.1

The rabies virus does not persist in the environment and is inactivated by factors including ultraviolet irradiation and desiccation. If the material in question is dry, the virus can usually be considered noninfectious.1

Find Out What Happens if Rabies Exposures Are Left Untreated

CDC Case Report: Missouri 20143

In 2014, a Missouri man arrived at a local hospital emergency room complaining of severe neck pain that radiated down his arm. He was diagnosed with cervical muscle strain and administered a muscle relaxant and anti-inflammatory. The next day he awoke with numbness and tingling in his arm. After suffering severe bilateral body tremors and sweating, he returned to the hospital where he was suspected of having a herniated disc. The man was instructed to take oral prednisone and oxycodone HCl/acetaminophen. As his symptoms progressed, he became distressed with fear and anxiety. Suffering from visual hallucinations, he was admitted to the hospital. The diagnosis was suspected serotonin syndrome secondary to the cyclobenzaprine.

After 2 days, he was transferred to another hospital for neurologic evaluation. His symptoms continued to worsen. Before being intubated and put on mechanical ventilation, the patient expressed an aversion to water. A battery of tests was conducted for a drug screen, tricyclic antidepressant levels, and an arbovirus panel. Tests were run for antibodies to Rocky Mountain spotted fever, ehrlichiosis, syphilis, and herpes simplex virus. All test results were negative.

The detection of rabies virus antigen in a skin biopsy determined the affliction to be rabies. Genomic sequencing established it as a variant associated with the tricolored bat. Because of the advanced stage of illness, the family elected to withdraw life support. The patient died soon after. Death came 14 days after the onset of symptoms.

Source: Centers for Disease Control and Prevention, Morbidity and Mortality Weekly Report, March 18, 2016

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

References

  1. 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.
  2. Crowcroft NS, Thampi N. The prevention and management of rabies. BMJ. 2015;350:g7827.
  3. Pratt PD, Henschel K, Turabelidze G, et al. Human rabies — Missouri, 2014. MMWR Morb Mortal Wkly Rep. 2016;65:253–256.