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| Colorado Wildlife Action Plan |
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| Sagebrush & Sage Species Conservation Strategy |
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| Colorado Wildlife Heritage Foundation |
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 One summer morning, a Colorado woman found a bat in her house, hanging behind a curtain. Intending to return the bat outdoors, she captured it in her hands and was bitten. She dropped the bat, which flew out the door and disappeared. The woman was treated for possible rabies exposure.
An 11-year-old girl also underwent rabies shots after she had attempted to rescue what she thought was a bird from the family cat. When she started to remove the "bird," it bit her on the finger. This bat was captured and tested positive for rabies.
These are examples of documented cases where people have encountered bats recently in Colorado. In each example, the bats exhibited warning signs that something was wrong.
Overall, most bats that inhabit our state are healthy, and the ones you see flying around at night probably aren't rabid. According to Bat Conservation International, "Bat rabies accounts for approximately one human death per year in the United States. Thus, some people consider bats to be dangerous." To put the rate in perspective," Merlin Tuttle, an active member of Bat Conservation International (BCI), states, "bicycle accidents killed 800 people, bee stings 95, and dog attacks 20 in the most recent year of reporting for the United States alone. Due to successful dog and cat vaccination programs, rabies is now the second rarest disease in the United States and Canada, behind polio." Clearly, bats do not rank very high among mortality threats to humans. Nevertheless, prudence and simple precautions can save lives.
The Colorado Division of Wildlife and the Colorado Department of Public Health and Environment want to inform you about rabies in bats—what suspicious behavior to look for, what to do if you find a bat or are exposed to a one, and how to prevent encounters with bats.
There are 18 species of bats known to live in Colorado. Some are here year-'round, and some migrate through the state. They can be found in every habitat—from the eastern plains to the high mountain forests and western deserts, from rural Colorado to downtown Denver. All of our bats eat insects; they play a valuable role in ecosystems by helping to control insect populations. Little brown bats, for example, have been known to catch and eat more than 150 mosquitoes and crop pests in less than 15 minutes. Bats also pollinate plants and crops.
Rabies is a virus that affects the central nervous system of mammals, causing a fatal inflammation of the brain and spinal cord. Rabies virus is shed in the saliva of an infected animal and is transmitted mainly through bites. It is also possible to get the virus through the introduction of saliva to open wounds, cuts or mucous membranes, like eyes, nose and mouth. "Symptoms most often develop about 10 days to seven months after infection, and death follows 2-12 days later," according to Bat Conservation International.
Rabies in Bats and Wildlife
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 Five species of wildlife are the main hosts of rabies in the U.S.—raccoons, skunks, bats, foxes and coyotes, in that order. In Colorado, bats have been the primary rabies host for the past 20 years. Between 1977 and 1996, 685 of the 697 animals (98 percent) that tested positive for rabies were bats. Since 1977, Colorado has recorded only 12 cases of rabies in species other than bats: 9 skunks, 1 cow, 1 fox and 1 cat. Three of the skunks, the fox and cat had been infected by a bat. The percentage of bats testing positive for rabies has averaged 15.2 percent. Statistics from Bat Conservation International show, "Worldwide, more than 30,000 humans die of rabies each year, 99% of cases resulting 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."
It's important to point out that this percentage reflects only bats found by people and submitted for testing. It's not a representative sample of all bats in Colorado. Studies have suggested that less than 1 percent of all bats may be infected with rabies.
In early stages of the disease, animals behave abnormally. They may lose their natural wariness of people, show up in places they don't usually frequent or become active at odd times of day. Bats are normally active at night. Seeing a bat during the day could be a sign that something is wrong, but doesn't necessarily mean it has rabies. A bat seen during the day may be injured. In this case, it may need rehabilitation (by a licensed rehabilitator). Also, bats seen during the day may have just been excluded from their roost by people or they may be juveniles.
Many bats roost in roofs, attics and sheds, without people knowing the bats are there. When people remodel, for example, a roost may be discovered and the bats might then be excluded. There are certain times of the year when it is better to exclude bats. If you need information on excluding bats from your home, call your Division of Wildlife office. An excluded bat might find a temporary roost site. But the site might be visible to people who may assume the bat is sick. If left undisturbed, the bat will leave in the evening to find a more suitable roost site.
Juvenile bats may also temporarily roost in a visible place. These bats are learning to fly, to eat on their own, to find drinking sources, and to find a roost site. As with many young animals starting out on their own, some juvenile bats die during this period. A bat that is seen during the day does not automatically mean that it has rabies, but be cautious. It might have the disease or it might be injured. The bat may have also been recently excluded from it's roost or it may be a lost juvenile.
Bats roost in trees, mines, caves and attics, or under rocks, roofs and siding. If you see one in an unusual place, such as on the side of a building or on the ground, beware. Bats also have remarkably accurate control of their flight, so another red flag is a bat that can't fly and repeatedly crashes into things. A good rule of thumb is anytime you see a bat acting abnormally, the chances are it is sick. Bats that have contact with people, that children find or pets capture are usually sick or injured and pose a greater risk of being rabid.
As the disease progresses, animals lose muscle control and coordination, stop eating and drinking and show signs of paralysis. According to BCI, "Rabies is often referred to as hydrophobia because victims fear swallowing. Drinking or eating can bring on muscle spasms of the throat. The fear of swallowing also accounts for saliva accumulation referred to as 'foaming' at the mouth. Infected animals may be either agitated and aggressive or paralyzed and passive. Dogs, cats, and other carnivores often become aggressive and try to attack humans and other animals, but bats are typically passive. Bats normally bite only in self-defense if handled, and aggressive behavior is rare, even when rabid."
"Early symptoms in humans include pain, burning, and numbness at the site of infection. Victims complain of headaches, inability to sleep, irritability, muscle spasms of the throat and difficulty swallowing. Convulsions may occur, followed by unconsciousness and death."
Next: Preventing Trouble
Last Updated: 9/9/2009
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