Controversy soars over issue of bats, their shrinking habitat and rabies

EARTH MATTERS AT HOME

November 27, 1991|By Susan McGrath | Susan McGrath,Los Angeles Times Syndicate

The subject is bats, again, because a surprisingly large and impressive group of readers appears to be passionate about bats, one way or another.

Not long ago I suggested that people help compensate for bats' shrinking habitat by putting up bat houses, which are much like bird houses. The column raised quite a squeal, first from the anti- and then from the pro-battists. Bat facts have been darting past my head at such speed that I think a few have gotten tangled in my hair.

So here's what we're going to do: Present both sides of the story. The two letters that follow present the case for and against bat houses quite cogently.

The first letter was signed by four public health officials in my hometown, Seattle, and appeared in the letters column of the Seattle Times.

"To the Editor: Bats are the reservoir for rabies in the Pacific Northwest. In Washington State, 10 percent of all bats tested (because of contact with humans or animals) from 1970 through 1989 for rabies were positive for the virus.

"Rabies is an illness which, unless vaccination is obtained very soon after the infecting bite, is virtually always fatal to people. Three of the four cases of human rabies acquired within the United States from 1980 through 1990 resulted from exposure to bats. . . .

"In addition to the life-threatening aspect of a bat bite, there is the cost and inconvenience, not to mention discomfort, of receiving post-exposure vaccinations for rabies.

"Because of this very grave health threat, local health officials feel that any campaign to encourage people to build bat houses near residences is irresponsible. An increase in the number of bats in areas where people live or work will increase the potential for bat exposures and will, no doubt, result in the use of more rabies vaccinations."

The health officials' letter elicited this response:

"Dear Sir or Madam: Bat Conservation International (BCI) was recently contacted by at least 20 of your readers to respond to a letter that appeared in the Times, implying that bats are commonly implicated in the spread of rabies in humans and other animals. Figures from the Centers from Disease Control (CDC) in Atlanta do not support this, nor do public health officials in California who have studied bats in order to determine the role of these animals in disease transmission.

"First, studies by Dr. Denny G. Constantine, a public health veterinarian in California and the world's leading authority on rabies and other diseases in bats, show that infection rates in randomly collected, naturally occurring bat populations (not the biased sample that makes up the population of animals that are turned into public health offices for rabies testing) range from about one in 1,000 (0.001) to one in 200 (0.005). .

"Second, Constantine documents that rabid bats generally do not become enraged and attack other animals. Usually, they become paralyzed and die. This phenomenon is reflected in CDC figures, which show that while rabies "outbreaks" are common in raccoons, skunks and foxes, such outbreaks have never been recorded in bats. This is noteworthy since many bat species occur in large colonies, sometimes consisting of millions of individuals. If bats were indeed 'reservoirs' of rabies, large-scale bat 'die-offs' would occur. They do not.

The letter goes on to say that BCI in no way encourages people to handle bats, and suggests that if people need information on how to exclude bats from their own homes, they may contact BCI, at P.O. Box 162603, Austin, Texas. 78716-2603. The letter is signed by BCI's science director.

So there you have it. If you are worried about rabies, get your dog and cat vaccinated today.

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