Navajo County in Arizona have issued a disturbing public health warning after fleas tested positive for the plague. The county made the warning in order to let residents know about the symptoms of bubonic plague, including buboes, fever and muscle pain.

Fleas collected in Coconino County, Arizona, also tested positive for Yersinia pestis, which causes the plague in humans. Navajo County asked people to take extra measures of precaution of they are in an area where the plague has been identified.

“Navajo County Health Department is urging the public to take precautions to reduce their risk of exposure to this serious disease,” they wrote on Facebook. “The disease can be transmitted to humans and other animals by the bite of an infected flea or by direct contact with an infected animal.”

They also issued advice for people who suspect they have already contracted it. Another indication of the plague could be incidents of sudden die-offs of rodents, rabbits or prairie dogs.

The plague is rare in America in recent times, and cases tend to be reported in the west of the country. Centers for Disease Control and Prevention.

If you have any of the following symptoms of the plague, you should contact your physician immediately:

  • fever
  • chills
  • headache
  • weakness
  • muscle pains
  • swollen lymph glands (called “buboes”) in the groin, armpits, or limbs.

Authorities from Navajo County have warned that the disease can spread throughout the bloodstream and infect the lungs if left untreated. However, it can be cured with antibiotics of treated early enough

The plague is rare in the United States, so if you contract it you should be okay if you treat it quickly. According to the Centers for Disease Control and Prevention, 12 people died from the disease between 2000 and 2015 (out of 96 cases of the disease).

Navajo County officials suggested extra precautions if you live in or visit the area, such as not handling dead animals and keeping your pets from roaming loose.

They also suggested using insect repellent if you visit areas that have been known to have the plague. Also avoid exposure to rodents wherever possible.