Volume 17, Issue 2, Summer 1999

Q&A: Bats and Rabies

What is rabies?
Rabies is an infectious viral disease that affects the nervous system of humans and other warm-blooded animals. A wide variety of mammals can contract the disease, but it is most often noticed in dogs, cats, foxes, raccoons, skunks, coyotes, bats, and livestock. Worldwide, more than 30,000 humans die of rabies each year, and 99 percent of cases result from contact with dogs. In the United States, due to highly successful dog vaccination programs, transmission from dogs is now rare, eliminating the vast majority of human cases.

How is rabies transmitted?
Rabies is nearly always transmitted by bite. Careless handling of wild bats (and failure to report bites) is the primary source of rabies exposure from bats. Contrary to popular belief, there is little chance that a bite could go unnoticed by a conscious adult. Bat bites are typically felt at the time of contact. There is an extremely remote possibility of being bitten unknowingly while deep in sleep, but if this were anything but the rarest of events, rabies would not be the second rarest disease in America.

People cannot get rabies just by being near a bat. There is no evidence that anyone can contract rabies by breathing air near bats in a building or yard. Two cases of airborne transmission were suspected to have occurred over 40 years ago within unique cave environments. However, no similar cases have occurred since, despite the fact that many thousands of people explore bat caves each year.

In addition, people cannot get rabies from having contact with bat guano (feces), blood, or urine. Rabies can be transmitted, however, by contact between an animal’s infected saliva or nervous tissues and a human’s open wound or mucous membranes of the eyes, nose, or mouth.

How can you tell if a bat has rabies?
Rabies infection can be confirmed only in a laboratory. However, any bat that is acting abnormally, is unable to fly, or is found in a place where bats are not usually seen is more likely than others to be injured or sick. Ninety to 95 percent of sick bats are not rabid, but taking a careless chance by handling such a bat could prove fatal.

How can rabies be prevented?
Dog and cat vaccination is the best prevention. Also, children should be taught never to handle wild or unfamiliar animals, even if they appear friendly. People who are at increased risk of exposure because they handle wildlife should receive rabies pre-exposure vaccinations.

What should you do if you are bitten by a bat?
Anyone bitten by a bat, or whose open wound or mucous membrane has come in contact with a bat’s saliva or nervous tissue, should wash the affected area thoroughly with soap and water and promptly seek medical attention. Whenever possible, the bat should be captured and tested for rabies. Post-exposure treatment should begin immediately unless the bat is confirmed negative. Even sick bats rarely bite except if handled, and people normally know if they are bitten. When uncertain, the bat should be tested.

What is the recommended treatment for exposure?
Modern rabies treatment is highly effective and relatively painless. Post-exposure rabies prophylaxis should begin as soon after exposure as possible. A series of six injections is administered over a period of 28 days.

Which bats have transmitted rabies to humans?
Five of the 45 bat species living in the continental United States have transmitted rabies to humans. These include the silver-haired bat (Lasionycteris noctivagans), the Mexican free-tailed bat (Tadarida brasiliensis), the big brown bat (Eptesicus fuscus), and two species that were not positively identified. These are suspected of having been western and eastern small-footed myotis (Myotis ciliolabrum and M. leibii). Any mammal can potentially transmit rabies.

A strain of rabies associated with silver-haired and eastern pipistrelle bats (Pipistrellus subflavus) has accounted for a large proportion of the few human cases associated with bats, but these species rarely live in buildings or bat houses. The bats typically seen around buildings have accounted for just eight human rabies cases since 1951, but they are the ones people now fear and make war on as a result of frightening public health claims. As such highly beneficial bats are destroyed, there is a real possibility that the species most implicated in transmission will, through reduced competition, be encouraged to live in closer proximity to humans.

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