Rare and Deadly Diseases: Rabies
Rabies is a disease caused by a virus that is fund in the saliva of infected animals. It can affect all mammals. Most of the time, it is transmitted to pets and people by bites, but open cuts can become contaminated as well. If rabies is not identified and treated, it causes painful death. Today, most rabies cases in the United States occur in wild animals like raccoons and bats. Pets account for less than 10 percent of reported cases.
The rabies virus attacks the central nervous system. Unfortunately, early symptoms of rabies in people are general things like fever and headache. As the disease progresses, neurological symptoms show up. They include insomnia, anxiety, confusion, paralysis, excitation, hallucinations, agitation, hypersalivation, difficulty swallowing, and fear of water. People who contract rabies die within days of the appearance of these symptoms.
Very few people in the United States die of rabies. This is due in part to public health measures that include vaccination of pets, animal control programs, good laboratories, and a rabies vaccine that can be given to those at risk as well as to those who have been bitten.
According to the CDC, more than 90 percent of rabies cases in animals occur in wildlife. Before 1960, most were in domestic animals.
Animal Bites Can Be Deadly!
Rabies is transmitted when an infected animal bites another animal or person, passing the virus in saliva. After initial infection, the virus enters a phase where it is difficult to detect. This phase can last for several days or several months. In some cases, the newly infected animal or person develops an effective immune response and doesn't get sick. In other cases, the virus is transported to the central nervous system.
The incubation period for rabies can be several days or several years, but it is normally one to three months. Once the virus gets into the central nervous system, it acts quickly to cause disease. This is when the previously described symptoms appear. After that, the infected animal or person will die within days.
In 2000, there were 7,369 cases of rabies in the United States. None of these were in people. 93 percent of the cases were in wild animals.
Testing for Rabies
In animals, the best diagnostic test uses brain tissue, and it can only be done after the animal dies. In people, there are several tests that are used. They require saliva, blood, spinal fluid, and skin biopsies. Antibody tests as well as DNA tests are done.
A diagnostic laboratory takes only a few hours to figure out whether an animal is rabid. This is important when a person has been bitten and is worried about exposure.
By the time symptoms show up, there is no treatment for rabies. However, there is a good rabies vaccine that can be used for people who may be at risk. The same vaccine is also effective after exposure. Domestic pets are also given rabies vaccines.
What if you're traveling abroad? Rabies is common in certain countries in Asia, Africa, and Latin America. It causes tens of thousands of deaths a year. Before you travel, talk to your doctor about risks and see whether you should receive a rabies vaccine.
What If I Think I've Been Exposed?
If you think you have been bitten by an animal that might be rabid, the first thing to do is wash the wound carefully, then call your doctor right away! Your doctor will figure out whether you need to have a rabies vaccine.
If you are a pet owner, be sure to keep vaccinations up to date for your dogs, cats, and ferrets (if you happen to have ferrets). This will protect your pets and it may even help to protect you! If your pet is bitten by a wild animal, get them to the veterinarian immediately. If there are stray or wild animals in your neighborhood, call animal control so that they are removed. Don't let your kids play with them or pet them!
Excerpted from The Complete Idiot's Guide to Dangerous Diseases and Epidemics 2002 by David Perlin, Ph.D., and Ann Cohen. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group (USA) Inc.