INFECTIOUS DISEASE Viral Illnesses • Chickenpox • Mumps • Postherpetic neuralgia • Croup • Measles • Rubella • Mononucleosis • Smallpox • Parvovirus infection • West Nile virus • Roseola • Rabies • SARS • Viral hemorrhagic fevers • Polio • Hand-foot-and-mouth disease

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Rabies is a serious viral disease that affects the central nervous system. It typically spreads by way of the saliva of infected animals — often, but not always, through a bite.

Once you're infected, the virus spreads from your muscle to your peripheral nerves to your spinal cord and brain. From initial flu-like signs and symptoms, the illness progresses to convulsions, hallucinations, paralysis or breathing failure and almost always death once the infection is established. It's important to seek treatment immediately after exposure.

Your risk of exposure to rabies in the United States is greater when you come into contact with a wild animal. Most rabies cases reported to the Centers for Disease Control and Prevention (CDC) each year occur in wild animals, including raccoons, skunks and foxes. Infected bats have transmitted most of the recent rabies cases in people in the United States. Domesticated animals such as cats, dogs and cattle account for only a small percentage of reported rabies cases. Most pets and domesticated animals receive vaccinations against rabies.

Each year a few people die of rabies in the United States. Most deaths occur because the person didn't seek medical assistance. Treatment consists of treatment to the wound plus a series of rabies shots, which prevent symptoms and death resulting from rabies infection. If you think you've been exposed to an animal with rabies, call your doctor as soon as possible.

Signs and symptoms of rabies usually appear within one to three months after exposure. Rabies is nearly always fatal once symptoms appear. Death from breathing failure often happens within a week after the appearance of signs and symptoms.

Early signs and symptoms of rabies in humans are general and not unique to the disease. They may include:

• Fever
• Headache
• Malaise

As the disease progresses, signs and symptoms may include:

• Insomnia
• Anxiety
• Confusion
• Slight or partial paralysis
• Excitation
• Hallucinations
• Agitation
• Excessive salivation (hypersalivation)
• Difficulty swallowing
• Fear of water (hydrophobia) because of the difficulty in swallowing

A bite's severity and its location on your body can determine how quickly signs and symptoms appear. A severe bite to your head might cause problems to appear in a much shorter time than might those of a bite to your leg. In rare cases, signs and symptoms might not appear for a year or longer after exposure to the virus.

Most often rabies transmission occurs through the bite of a rabid animal. Rarely, people contract rabies when saliva from an infected animal comes in contact with their eyes, nose, mouth or a wound. This may occur if you're licked by an infected animal.

Inhaling the rabies virus is another potential route of exposure, but one likely to affect only laboratory workers.

Petting a rabid animal or coming into contact with the blood, urine or feces of a rabid animal isn't considered an exposure to rabies and doesn't indicate a need for treatment.

You're at greatest risk of contracting rabies if your activities bring you into contact with the rabies virus or a potentially rabid mammal. People at risk can include veterinarians, animal caretakers or handlers, laboratory workers, cave explorers, forest rangers and people visiting bat-inhabited caves.

You're also at risk if you plan to travel to areas where rabies isn't well controlled, such as parts of Africa, Asia, Central America and South America.

If you think you may have been exposed to an animal with rabies, call your doctor immediately. Thoroughly wash the wound or area of exposure with soap and water. Quick action is important. Once the earliest signs and symptoms appear, death almost always follows. Promptly contacting your doctor after a potential rabies exposure greatly increases your chance of surviving. No one in the United States has contracted rabies after receiving prompt and appropriate treatment after an exposure.

If you awaken and find a bat in your room, it's possible you had contact with the bat without knowing it. Bats have small teeth that don't always leave noticeable marks. In the case of small rodents, including squirrels, a bite isn't likely to transmit rabies, but it's still best to consult your doctor to make a treatment decision. Your local or state health department will have up-to-date information on the types of animals in your local community that are potential carriers of rabies, and those in which rabies is unlikely.

If you've been bitten or have had contact with an animal that may have rabies, certain information may help your doctor determine your risk of contracting rabies and how to treat you. Take note of the following:

• Where the incident occurred
• Description of the animal
• If you were bitten, whether the animal was provoked or confronted
• The vaccination status of a domesticated animal
• Whether the animal can be safely captured to be tested for rabies

Once a potentially rabid animal is captured, it may be confined for observation. Another option is for health professionals to conduct tests on the animal's brain tissue to determine whether it has rabies. Testing can be done quickly, but only after the animal is dead.

Testing humans to identify or rule out rabies infection requires a number of tests using blood, saliva, spinal fluid, brain tissue or skin tissue taken from the nape of the neck.

If your doctor determines that you likely were exposed to rabies, treatment begins at once. The sooner you begin treatment, the greater your chance of recovery.

If you live in the United States and receive treatment for rabies after an animal bite, treatment — called post-exposure prophylaxis — consists of one dose of rabies immune globulin and five doses of rabies vaccine over a 28-day period. Rabies immune globulin and the first dose of rabies vaccine are administered as soon as possible after you've been exposed and have reported the exposure to your doctor. You're given the immune globulin by injection around the site of the bite, and you receive injections of the vaccine into your upper arm muscle.

Immune globulins are disease-fighting proteins that provide you with temporary antibodies. The rabies vaccine helps your body start producing its own antibodies. Antibody production takes time, but the antibodies produced by your body provide longer lasting protection than do the ones contained in rabies immune globulin.

You might have a mild physical reaction to the vaccines. Watch for reactions such as swelling or redness where the injection occurred. Headache, fever, nausea, muscle aches and dizziness are other possible side effects. Contact your doctor if side effects cause you discomfort.

The first thing to do if you've been bitten by an animal is thoroughly wash the wound or area of exposure with soap and water. This is one of the most effective methods to decrease the chance of infection.

If soap isn't available, for example, when hiking, you can use water alone. But be sure to wash with soap and water as soon as possible. Allowing the wound to bleed can also help clean it.

Ways to help prevent exposure to rabies include:

• Keep your pets and other domesticated animals up-to-date with regular animal rabies shots.
• Keep your dog on a leash when outside of your yard. Don't leave it chained up inside your yard.
• Avoid contact with wild or unfamiliar animals, whether they're alive or dead.
• Seal or close any openings where animals might find entry into your home.
• Report stray animals or any that act strangely or sick to your local animal control authorities. Keep animal control's phone number near your phone.
• Teach your children to never handle unfamiliar animals. Remind your children of this saying about handling animals: "Love your own, leave other animals alone."
• If you're traveling, avoid direct contact with wild animals and be cautious around dogs in developing countries.

If your work or activities might bring you into contact with the rabies virus or a potentially rabid mammal, consider getting a preventive vaccination. This vaccination — called pre-exposure prophylaxis — involves three injections over three or four weeks. A booster shot can maintain the vaccination's effectiveness.

Determine your risk before traveling
Talk to your doctor or a travel medicine specialist before visiting developing countries in Asia, Africa or Latin America. In many of these countries, dogs are the major carriers of rabies. Children may be at particular risk since they might be more likely than adults to be approached by stray or rabid animals. Your doctor can help you gauge your risk of exposure to rabies and whether to have pre-exposure prophylaxis. You can also discuss how you would handle an exposure. Some areas of the world don't have complete post-exposure treatment readily available.