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The Natural History of Disease

Rabies

We hear a lot about bats carrying rabies, which elicits fear toward these animals who, strictly speaking, do us much more good than harm. However, a percentage of bats carry rabies, and they are a common vector (transmitter) nationwide. What is the story? What is prudent behavior?

Background

Rabies is a deadly viral disease of the central nervous system that can affect most mammals. Most wild animals can get infected and the most susceptible include bats, raccoons, skunks, coyotes, foxes, and wolves. Domestic animals can be vaccinated against rabies, but if they are not vaccinated they are vulnerable. Cats currently make up the most reported cases among domestic animals in the United States. Because of our domestic animal control, rabies has become a rare disease. Occasionally humans are infected with rabies through non-bite exposure. Laboratory workers, cavers, and those working in buildings where they are constantly exposed are at risk for this unusual mode of infection.

According to the Center for Disease Control (CDC), there were five deaths from rabies in 2000, with four attributed to bats. The cases were from California, New York, Georgia, Minnesota, and Wisconsin. The patients reported contact with bats but did not know if they had been bitten. One man, living on the upper floor of an old house, reported bats in his living quarters, and one actually landed on him while he slept. Later a colony of two hundred Mexican free-tail bats were found in his attic. CDC data indicates that this number of cases is about standard for a year in the 1990s.

Prudent precautions include not handling sick or dead bats and rodents, excluding bats from dwellings where people live and work, and seeking immediate medical attention if infection is suspected.

Since there is no diagnostic test for rabies before the onset of symptoms, any animal bite should be investigated. If the animal is available for quarantine, it can be monitored and tested for rabies. Every year as many as 18,000 people in the U.S. get rabies shots because they may have been exposed to the disease. Worldwide 40,000 die from rabies (99% of the rabies due to dog rabies) but the World Health Organization estimates 10 million are treated after being exposed to animals that may have rabies.

What to Do

If a bat touches you in any way you should wash the wound thoroughly and seek immediate medical attention. The animal should be analyzed if possible. Do not wait for symptoms to appear; by then it is too late. Also, the symptoms can be confusing. The five patients that died in 2000 were originally diagnosed for heart attack, limb numbness, carpel tunnel syndrome, and bowel obstruction. If bats are living in your home or where people work see the information below about methods of exclusion.

Inform yourself

FAQs About Bats (San Diego Natural History Museum)

Two excellent organizations devoted to conservation of bats have information on exclusion procedures and compelling facts and stories about these useful animals.
California Bat Conservation
Bat Conservation International

Rabies Webpage Just for Kids Centers for Disease Control

Information for this essay was compiled using information from
The California Department of Health Services
Rabies (drkoop.com Medical Encyclopedia)

Zoonoses | Field Guide