FIRST REPORTED in the United States in 1753, rabies attacks the central nervous system. A rhabdovirus of the genus Lyssavirus, it's been found in every state except Hawaii.
Progressing through nerves to the brain, rabies causes encephalitis, muscle spasms, and other agonizing signs and symptoms. Unless an infected person is treated before symptoms appear, rabies is nearly always fatal.
Worldwide, rabies kills more than 30,000 people annually. However, largely because of widespread vaccination of domestic animals in the United States, only 36 people died of rabies here between 1990 and 2001.
More than 90% of animal cases now identified in the United States occur in wild animals, such as bats, raccoons, skunks, and foxes. Very rarely, the virus infects rabbits, squirrels, rats, and opossums.
Rabies is usually transmitted to humans through the saliva of an infected animal; however, it may also be transmitted when infectious material from an animal gets into a person's mucous membranes or an open wound. The incubation period before symptoms appear can last several days or even years, but the average time is 3 to 8 weeks.
Providing postexposure prophylaxis
If your patient has been exposed to a potentially rabid animal and the animal's rabies status is unknown, vaccination before symptoms appear can save her life (see Postexposure Prophylaxis Stops Rabies in Its Tracks). For information on when vaccination is indicated, see Human Rabies Prevention—United States, 1999 Recommendations of the Advisory Committee on Immunization Practices (ACIP) (http://www.cdc.gov/mmwr/preview/mmwrhtml/00056176.htm) and consult your local and state health departments.
Without prophylactic treatment, an infected patient may experience flulike symptoms, such as headache, fever, and malaise, for a few days. She may also experience pruritus, pain, or paresthesias at the exposure site. Days later, as the virus invades the central nervous system and causes encephalitis, she may become agitated, anxious, or confused and experience paresis or paralysis, delirium, and hallucinations. Muscle spasms in her throat may cause drooling. These symptoms, which last 2 to 10 days, are followed by coma and death.
Once a patient develops signs and symptoms of rabies, treatment is palliative. Use standard precautions to protect yourself and others from exposure.
People who work with animals and those traveling to endemic areas should consider receiving preexposure prophylaxis at least 30 days before potential contact with an animal: three doses of rabies vaccine I.M. in the deltoid muscle and a one-dose booster every 2 years (depending on the titer level).
Help your patients avoid rabies exposure by providing these tips:
- Always seek medical help if you're bitten by a stray or wild animal.
- Keep pets vaccinated and supervise them when they're outside.
- Contact your local animal control agency if you notice abnormal behavior in stray or wild animals.
- Never feed or handle wild animals.
- Prevent bats from occupying your home or other areas where they may come in contact with people and pets.
- Before traveling to Asia, Africa, or Latin America, contact your health department and health care provider about the need for vaccination.
By educating patients and acting quickly when potential exposure is suspected, you can help prevent this deadly disease in your patients.
Postexposure prophylaxis stops rabies in its tracks
Follow these steps to treat a patient who's been bitten by a potentially rabid animal.
- Immediately flush the wound and clean it with soap and water to remove the animal's saliva.
- Administer one 1-ml dose of rabies vaccine in the deltoid and 1 dose of human rabies immune globulin (HRIG) into and around the wound. The amount of HRIG given is based on the patient's weight: administer 20 international units per kg of body weight. Infiltrate it into and around the wound as thoroughly as possible and give the remainder I.M. into the gluteal region.
- Evaluate the patient's need for tetanus prophylaxis and antibiotics.
- Avoid closing or suturing the wound unless absolutely necessary.
On days 3, 7, 14, and 28, administer 1 dose of rabies vaccine in the deltoid muscle.