Colorado health officials have issued a warning to Boulder County residents after bubonic plague was found in fleas taken from a prairie dog.

Flea samples were taken from a Boulder property when a homeowner notified officials of several dead prairie dogs on the property.

The neighborhood has been posted with signs warning residents to protect themselves and their pets.

The plague has been active in the area every year since 2005, according to Heather Swanson, a wildlife ecologist for Boulder Open Space and Mountain Parks, but this is the first confirmed case in the county since 2011, when a pet cat and a dead squirrel tested positive for it.

Plague occurs naturally in Colorado, and bubonic plague is the most common form. It occurs after a bite from an infected flea and can be spread to humans when infected fleas from animals bite a human.

"Household pets, such as dogs and especially cats, can get plague themselves or carry infected fleas home to their owners. In rare instances, plague can be transmitted to people from cats sick with plague,” states a news release issued by the Boulder County Health Department.

Because fleas don’t travel long distances, health officials say the plague is unlikely to spread, but locals should still be on the lookout for symptoms, which include fever, headache, nausea, vomiting and pain and swelling in the lymph nodes.

People who experience such symptoms should seek medical attention immediately.

The plague can be treated with antibiotics, but treatment is most effective when the disease is diagnosed quickly.

Health officials recommend that Boulder residents take the following precautions:

  • Avoid fleas. Protect pets with flea powder or drops, or a new flea collar. Keep pets on a leash and out of wild rodent habitats.
  • Avoid all contact with wild rodents, including squirrels; do not feed or handle them.
  • Prevent rodent infestations around your house. Clear plants and material away from outside walls, reduce access to food items and set rodent traps.
  • Treat known rodent sites around your home with flea powder or a suitable insecticide.