FLAGSTAFF, Ariz., April 6 (UPI) -- Arizona health officials and wildlife managers are monitoring flea infestations more closely after several specimens in Picture Canyon, near Flagstaff, tested positive for Yersinia pestis, the bacteria that causes the disease known as the bubonic plague.
Officials grew concerned when they were alerted to a prairie dog den that appeared to features an unusually large number of dead or dying prairie dogs. Several surrounding burrows were tested, revealing the culprit to be the plague.
"It looked like something that could be associated with death due to plague," Randy Philips, division manager of the local health services district, told the Arizona Daily Sun.
Nearby burrows are now being cleared and disinfected, in an effort to stem any possible outbreak of the disease. Late last week, following the positive test, officials returned to test a much broader area for the dangerous bacteria. Those results are due back later this week.
The plague isn't new to Arizona. The disease has been firmly established in the Grand Canyon State, as well as Colorado and New Mexico, for some time now. Every year, a handful of people are infected with the disease -- the vast majority in one of those three states. Instances occasionally occur in other parts of the West.
As the Arizona Department of Health Services explains: "Plague activity in nature has been known to wax and wane over time, and this is influenced largely by climate conditions and rodent and flea populations."
The disease-causing bacteria is carried by rabbits and small rodents, including prairie dogs, ground squirrels, rats and mice. Prairie dogs are especially vulnerable to the disease due to their social nature. Outbreaks can quickly wipe out 90 percent of a local prairie dog population.
"If you normally see prairie dogs then next day they're gone, there is a good chance plague is coming," said Dave Engelthaler, programming director with pathogen research nonprofit TGen North.
Officials have posted signs at trailheads in Picture Canyon, warning visitors of the plague's presence. It's best to avoid close or direct contact with rodents and their living quarters. Dogs who come in contact with or feed on infested rodents can also carry the infected fleas or the disease itself.
Plague symptoms typically manifest themselves within six days of infection and include fever, chills, headache, weakness, muscle aches and swollen lymph nodes. While the disease can occasionally prove deadly -- it carries a roughly 10 percent mortality rate -- it is usually treatable with antibiotics when caught early enough.
In 2012, an Oregon man was infected when his cat bit him as he tried to dislodge a partially-eaten mouse from the feline's throat. He lost several fingers and toes to the infection before the antibiotics kicked in.