Rabies

Transmission

About 7,000 cases of rabies in animals are reported each year to the Centers for Disease Control and Prevention (CDC). Raccoons are the most common carriers of rabies in the United States, but bats are most likely to infect people. Almost three quarters of rabies cases between 1990 and 2001 came from contact with bats.

Skunks and foxes also can be infected with rabies, and a few cases have been reported in wolves, coyotes, bobcats, and ferrets. Small rodents such as hamsters, squirrels, chipmunks, mice, and rabbits are very rarely infected with the virus.

Because of widespread vaccination programs in the United States, transmission from dogs to people is very rare. Outside the United States, exposure to rabid dogs is the most common cause of transmission to humans.

An infected animal has the rabies virus in its saliva and can transmit it to a person through biting. In rarer cases, an animal can spread the virus when its saliva comes in contact with a person's mucous membranes (moist skin surfaces, like the mouth or inner eyelids) or broken skin such as a cut, scratch, bruise, or open wound.

After a bite, the rabies virus can spread into surrounding muscle, then travel up nearby nerves to the brain. Once the virus reaches the brain, the infection is fatal in almost all cases.

Signs and Symptoms

The first symptoms can appear from a few days to more than a year after the bite occurs.

One of the most distinctive signs of a rabies infection is a tingling or twitching sensation around the area of the animal bite. It is often accompanied by a fever, headache, muscle aches, loss of appetite, nausea, and fatigue.

As the infection progresses, someone infected with rabies may develop any of these symptoms:

• irritability
• excessive movements or agitation
• confusion
• hallucinations
• aggressiveness
• bizarre or abnormal thoughts
• muscle spasms
• abnormal postures
• seizures (convulsions)
• weakness or paralysis (when a person cannot move some part of the body)
• extreme sensitivity to bright lights, sounds, or touch
• increased production of saliva or tears
• difficulty speaking

In the advanced stage of the infection, as it spreads to other parts of the nervous system, these symptoms may develop:

• double vision
• problems moving facial muscles
• abnormal movements of the diaphragm and muscles that control breathing
• difficulty swallowing and increased production of saliva, causing the "foaming at the mouth" usually associated with a rabies infection

If Your Child Is Bitten by an Animal

If your child has been bitten by an animal, take the following steps right away:

• Wash the bite area with soap and water for 10 minutes and cover the bite with a clean bandage.
• Immediately call your doctor and go to a nearby emergency department. Anyone with a possible rabies infection must be treated in a hospital.
• Call local animal-control authorities to help find the animal that caused the bite. The animal may need to be detained and observed for signs of rabies.
• If you know the owner of the animal that has bitten your child, get all the information about the animal, including vaccination status and the owner's name and address. Notify your local health department, particularly if the animal hasn't been vaccinated.
• If you suspect that your child has been bitten by an unknown dog, bat, rat, or other animal, contact your doctor immediately or take your child to the emergency department.

Treatment

At the hospital, it is likely that the doctor will first clean the wound thoroughly and make sure that your child's tetanus immunizations are current.

To keep any potential infection from spreading, the doctor may decide to start treating your child right away with shots of human rabies immune globulin to the wound site and vaccine shots in the arm. This decision is usually based on the circumstances of the bite (provoked or unprovoked), the type of animal (species, wild or domestic), the animal's health history (vaccinated or not), and the recommendations of local health authorities.

Prevention

You can reduce the chances that your family is exposed to rabies. Vaccinate your pets — dogs, cats, and ferrets can be infected by rabies. Report any stray animals to your local health authorities or animal-control officer. Remind kids that animals can be "strangers," too. They should never touch or feed stray cats or dogs wandering in the neighborhood or elsewhere.

As a precaution against rabies, call your doctor if:

• your child has been exposed to an animal that might have rabies, but is too young to describe the contact with the animal
• your child has been exposed to bats, even if there is no bite
• you plan to travel abroad and may come into contact with rabid animals, particularly if you're traveling to an area where you might not have access to health care

Reviewed by: Joel Klein, MD
Date reviewed: November 2010