What is rabies?

Rabies is a disease caused by a virus that can affect the brain and spinal cord of mammals, including humans.

Animals infected with rabies can spread the disease through their saliva or brain matter, so people may be exposed to the disease if they're bitten by an infected animal or if they touch an infected animal corpse's brain.

In extremely rare situations, a person can get rabies without being bitten by a rabid animal (nonbite exposure). Humans have acquired rabies by handling a rabid animal or by inhaling airborne virus in places where it exists in high quantities, such as caves filled with bats.

Where is rabies prevalent?

Rabies is more common in developing nations than in North America, where widespread animal vaccination programs have limited the disease's spread to humans. The most common rabies carriers in the United States are bats, raccoons, skunks, foxes, and coyotes.

Sometimes the rabies spreads to pets, such as dogs, cats, and domestic ferrets, but thanks to vaccination programs, this occurrence is rare. A pet that always stays indoors is especially unlikely to be exposed to the virus.

What are the signs of rabies in animals?

Rabid animals (those infected with rabies) may show noticeable behavioral changes such as acting strangely or biting someone.
An animal that exhibits any of the following signs may have rabies:

• No fear of humans shown by a wild animal
• Shyness in a usually friendly pet
• Restlessness, excitability, aggression, or sudden mood changes
• Excessive drooling
• An animal that is normally active at night (such as bats, raccoons, and skunks) being active during the day
• Eating substances not normally eaten
• Paralysis, which is sometimes the only sign

Animals displaying strange behavior are often assumed to be rabid, but whether they actually have rabies or not depends on factors such as:

• The type of animal. (Bats, skunks, raccoons, foxes, and coyotes are more likely to carry the virus than other animals.)
• The behavior of the animal, such as excessive drooling or aggression.
• Risk for rabies in a specific geographic area. (Most rabies cases cases reported in Southeast Texas come from bats.)
• The date of the animal's last rabies vaccination.

What are the symptoms of rabies in humans?

Humans bitten by a rabid animal typically do not have any symptoms during the first four to six weeks. Early signs include pain and numbness at the site of the bite followed by other vague symptoms that are often confused with those of other conditions.

Early symptoms of rabies include:

• Fever
• Cough or sore throat
• Pain, burning, itching, tingling, or numbness at the site of the bite or original exposure
• Abdominal pain
• Anxiety or restlessness that gradually worsens and may develop into extreme agitation

Later symptoms are more distinctive and may include:

• Periods of normal behavior alternating with unusual behavior like anxiety, agitation, hallucinations and delirium
• Fear of water (hydrophobia) or fear of air (aerophobia).
• Muscle spasms in the face, neck, and/or diaphragm, followed by seizures
• Paralysis (often the only symptom of a rare paralytic form of rabies associated with rabies from vampire bats)
• Wide fluctuations in temperature, pulse, and blood pressure
• Coma; heart and respiratory failure

Because its symptoms mirror other conditions, rabies in humans can be difficult to diagnose. Some tests can help; the direct fluorescent antibody (DFA) test detects rabies virus protein in a person's tissue, and the polymerase chain reaction (PCR) assay detect virus proteins' DNA in a saliva, and spinal fluid.

To prevent rabies, individuals must be treated before symptoms develop. Because the rabies virus damages the central nervous system, including the brain and spinal cord, once the symptoms developed, the disease is nearly always fatal.

How is rabies treated?

After possible exposure to the rabies virus, proper wound care and vaccinations are the best ways to stop the spread of infection.

If you are bitten by an animal you can reduce your risk of infection by cleaning the wound immediately with plenty of soap and water. Ask your doctor if further care is needed.

If you have been exposed to rabies, you may be given a series of vaccinations that help the body's immune system destroy the disease in its early stages. When the vaccinations are given before serious symptoms appear, they usually prevent infection from developing, and recovery is likely. After the later serious symptoms develop, vaccines are no longer effective, and death is guaranteed.

Whether or not you receive the vaccine depends on the type of exposure you've had to the virus as well as the type of animal involved. Your physician or health department can help determine if you need vaccination.

How can I protect myself from rabies?

The best way to protect yourself from the rabies is to avoid contact with the virus.

• Have pet dogs, cats, and domestic ferrets vaccinated against rabies. If your pet was owned by someone else first, ask the previous owner or veterinarian for proof that the animal received the rabies vaccine.
• Avoid all contact with bats, the primary culprits of rabies infection in North America.
• Never try to touch pet or catch wild animals such as raccoons, skunks, foxes, and coyotes. Teach children to stay away from these animals.
• Secure garbage and other materials that attract animals.
• Secure open areas of your home, such as pet doors, chimneys, unscreened windows, or any place wild or stray animals could enter.
• Never handle a dead animal. In particular, avoid any contact with the brain tissue from a dead animal.
  

If you are bitten or have risky contact with an animal:

• Immediately clean the wound or area of contact thoroughly with soap and water. Ask your health professional for further instructions. 
• If the animal is a dog, cat, or domestic ferret, try to locate and contact the owner. If you can't find the owner, contact the local animal control to safely capture the animal.
• If the animal is wild, do not attempt to capture or destroy it. Identify the species of animal and notice whether its behavior is unusual. If you have already killed the animal, keep the head, but do not touch the brain, which may transmit rabies. The local or state health department can test the brain for the virus.
• Contact the local or state health department to report a bite or serious scratch. That agency will know whether the animal  is likely to be infected with rabies in your area. Officials also may attempt to capture or destroy a wild animal so that it can be tested.

You may need to be vaccinated against rabies if you travel to rural areas of countries where rabies is a risk. The disease is more common in developing countries throughout Asia, Africa and Latin America, where the majority of human infections are caused by dog bites.

To find out more about rabies, contact your doctor or health department or check out Web MD: www.webmd.com/hw/infection/hw181257.asp?pagenumber=2#top.

For information about rabies in Texas, check out the Texas Department of State Health Services web site: www.dshs.state.tx.us/idcu/disease/rabies/