DENVER -- A coyote from Prowers County has tested positive for rabies, the Colorado Department of Public Health and Environment said Tuesday, the first case in Colorado in at least 30 years.

Health department officials said the coyote was shot and killed after it attacked a woman last Friday.

The 87-year-old woman bitten by the coyote is undergoing preventative rabies treatment, health officials said.

Prowers County Public Health Department has placed a public health alert order requiring dogs and cats in the county to be up-to-date on rabies vaccinations, officials said.

Under Colorado law, licensed veterinarians must administer rabies vaccinations to pets.

Brain tissue from the coyote is being sent to a U.S. Centers for Disease Control laboratory for typing of the rabies strain, officials said. The CDC lab has tests that can tell if a rabies strain is from a bat, skunk, Mexican dog or other animal, giving a clue as to how the coyote was infected.

"In the past, isolated rabies cases in animals have turned out to be a bat strain, usually meaning the infected animal found and ate a bat," said John Pape, an epidemiologist with the Colorado Department of Public Health and Environment. Bat strains of rabies virus have limited risk of becoming established in other animal species and spreading to other wildlife and pets, Pape added.

"However, given the location in the southeastern corner of the state, it is possible that this case could be a skunk strain of rabies," Pape said.

The skunk strain is commonly found in Kansas and Oklahoma, and has occasionally shown up in eastern Colorado, Pape said.

Rabies is a virus that affects the nervous system of humans and other mammals, resulting in a fatal disease. The virus is shed in the saliva of infected animals. People and animals get rabies from the bite of a rabid animal or contact with saliva from such an animal.

To prevent possible exposure to rabies, state health experts warned Coloradans to keep their pets' vaccinations up to date, leave bats and other wildlife alone and, if they suspect a family member or pet has been bitten, to hold the animal for possible rabies testing.

Pape said that rabies in bats is quite common in Colorado, with 30 to 60 confirmed cases each year. However, rabies in animals such as skunks, raccoons, foxes and domestic animals is rare. Cases of rabies found in Colorado in cats, foxes, skunks and cattle over the past 20 years have been due to exposures to bats or have been imported from states where rabies is more prevalent.