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When Rabies Strike U.S., Bats Usually to Blame

ASSOCIATED PRESS

A man woke up in a motel room in the middle of the night to find a bat clinging to his left shoulder.

He jumped out of bed, grabbed the creature and impulsively flushed it down the toilet. His wife followed him into the bathroom and looked at his skin, but she could find no sign of a bite. So the couple went back to sleep. And that was the end of the matter.

For a while.

Two months later, the man began to feel ill. He lost his appetite, and a sharp pain ran from his left ear, down his face, all the way to his chest.

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His doctor suspected a sinus infection. But matters grew worse. In a few days he was admitted to the hospital, agitated and confused. He itched all over.

Doctors gave the man antibiotics and anxiety drugs. Nevertheless, he broke out in a fever that rose to almost 104. He lost control of his eye movements. His body twitched involuntarily. He could not swallow his own saliva.

Then his blood pressure fell, and his breathing weakened. At this point his doctors had an awful thought: rabies. They still were not sure, and even if they had been, it would not have mattered. By the time rabies causes symptoms, it is untreatable and relentlessly fatal.

The man fell into a coma and died. An autopsy confirmed the doctors’ suspicion.

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Not long ago, the medical investigation might have ended there. But now technology lets doctors identify the source of any virus that causes rabies.

It turned out this man died from the kind of rabies carried by bats. Furthermore, they could tell which species. He almost certainly was bitten by one of two quite rare kinds, either the silver-haired or the Eastern pipistrelle.

The mention of rabies still triggers images of frothing dogs. Old Yeller, maybe, or Cujo. And in most of the world, dog bites are how the disease usually spreads.

But in the United States, rabies has almost disappeared as a human affliction. Almost, but not quite. And the few cases that occur each year are nearly always spread by bats.

The motel victim, a 71-year-old man from Houston, died in 1997. He was one of four Americans killed by rabies that year. All of them caught it from bats.

According to federal heath statistics, there were four U.S.-acquired cases, all from bats, in 1995. In 1996 there were two cases, both from bats. Last year there was just one, again from a bat. So far this year, no U.S. rabies cases have been reported.

Since 1980, 25 people have caught rabies in the United States, all but three of them from bats, according to federal statistics. (The exceptions: two dogs and a skunk.) So how did these mouse-size flying mammals come to be the chief spreaders of such an awful disease?

One possible explanation can almost certainly be ruled out, says Merlin D. Tuttle, founder of Bat Conservation International in Austin, Texas, and a bat aficionado: “There is no evidence at all that there is more rabies in bats today than when Columbus discovered America.”

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Nor are bats getting nastier. While the first case of bat-to-human rabies was not documented in the United States until 1953, experts say it is unlikely that rabid bats are biting humans any more frequently now than they have through the centuries.

Instead, it appears that bats’ unfortunate distinction results from two things: technology that lets scientists pin the disease squarely on them and the remarkable elimination of rabies from other critters that carry the virus.

Testing like the kind used to find the source of the Texas man’s rabies has been especially important. Scientists read the virus’ genetic material. They can tell by the genetic pattern whether it came from a cat, a raccoon or a particular variety of bat.

Since those who eventually die of bat-borne rabies almost never remember being bitten, most of the cases of the last 20 years would never have been convincingly traced to their source without the genetic test.

Still, rabies from bats is exceedingly rare. It is only the absence of other sources of rabies that makes it stand out.

At the turn of the century, more than 100 Americans died of rabies each year. The culprit was usually a dog. In fact, around the world, rabies is still a big health problem. At least 40,000 people die annually, and 99% of the cases are spread by dog bites.

In the United States, rabies began to decline in the 1920s. Routine rabies shots for dogs made a big difference, along with leash laws, quarantines and the efforts of dogcatchers.

By 1960 rabies had grown so rare in dogs, cats and other domestic animals that wildlife became the primary reservoir of the virus. For the next 30 or so years, skunks were the primary carriers. They were overtaken in the 1990s by raccoons.

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Despite the prevalence of the disease in raccoons, however, there has not been a documented U.S. case of someone dying of rabies caught from a raccoon.

One reason for this is that anyone who is bitten by a raccoon will almost certainly seek a rabies shot. People associate rabies with attacks by four-legged carnivores, and a raccoon bite is hard to ignore.

However, bat bites are much smaller. Anyone bitten while awake will almost certainly feel a pinch, but the bat’s needle-like teeth may leave no visible wound. Failure to recognize bites probably accounts for most of the bat rabies cases.

For instance, a man in Washington state who died of rabies in 1997 liked to garden at night. Medical investigators believe he probably put his hand on a rabid bat without knowing it while puttering around outside.

The same year, a New Jersey man twice captured bats by hand after they got into his living room. He could not remember being bitten, but he too got bat rabies and died.

Such deaths could almost certainly be eliminated with rabies shots. Once these were fiercely painful injections in the abdomen, but now they are five easy shots in the arm over four weeks.

To work, the shots must begin soon after exposure to rabies. The virus infects the nerve endings in the skin. Then it spreads up the nerves to the brain. This journey can take months, even years. Vaccination prepares the body to destroy the virus as it emerges.

Once the disease begins to produce symptoms, there is no treatment. The classic sign of the disease is hydrophobia, a fear of water. If victims attempt to drink, their throat muscles go into spasm and they choke. By then, the disease is invariably fatal.

The U.S. Centers for Disease Control and Prevention estimates that about 40,000 Americans get rabies vaccinations each year, and they typically cost about $2,000 for the full series of shots. New CDC guidelines recommend vaccination whenever there is “direct contact” between a human and a bat, unless the person can be sure he or she was not bitten or scratched or touched bat saliva.

Generally, the risk is low if a bat gets into the house, especially if everyone is awake and no one touches the animal. However, the CDC says shots should be considered if someone wakes up to discover a bat in the room, or if a bat is found in a room with a child or someone who is mentally disabled or in a drunken stupor.

A bat flying overhead outdoors is no threat. But people should never touch bats they find lying on the ground.

“The reason we call wildlife wildlife is because it’s wild,” says W. John Pape, an epidemiologist at the Colorado health department. “If any kind of wildlife--not just bats--allows you to approach it, it’s sick or injured, and you will probably end up getting bitten. Wildlife is best viewed from afar.”

If someone does happen to be bitten by a bat, there’s a sizable risk the animal is rabid. Pape’s department tested 4,470 dead bats that had been sent in over the last 20 years after contact with people. Fifteen percent were rabid, including 30% of those that had bitten someone.

Still, none of the 69 Colorado people bitten by rabid bats ever got rabies. In fact, Colorado has not had a rabies case since 1931, and that one was caused by a dog.

The Colorado figures show that human rabies is exceptionally rare, even when rabid bats are around. Bats are useful creatures that eat phenomenal amounts of mosquitoes and other bugs, and experts say fear of rabies is not usually a good reason to kill them.

“Public health officials have not declared a jihad on bats,” says Charles E. Rupprecht, the CDC’s rabies chief. “No one recommends wholesale slaughter of bats. We are trying to manage very difficult public health situations for a rare disease.”

However, Tuttle of the bat conservation organization complains of overzealousness by public health officials. He worries that they sometimes frighten people into killing bats that live harmlessly in caves or under the eaves of houses.

His group estimates that more than half of the American bat species are in severe decline or are already listed as endangered.

“Almost any bat researcher in America would agree that a key factor in bat decline is human fear,” says Tuttle. “And nothing has done more to exacerbate that than grossly exaggerated claims of how bats can give you rabies.”

What to Do

In the unlikely event that you are bitten by a bat, health experts say:

* Wash out the wound with soap and water.

* If possible, capture the bat so it can be tested. This is the only way to know for sure whether the animal is rabid.

* See a doctor immediately to begin a series of rabies vaccinations. This can be avoided only if tests on the bat prove that it does not carry the disease.


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