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EVERGREEN, Colo. (KDVR) — A cat has tested positive for the bubonic plague after becoming infected from a suspected encounter with a sick rodent, possibly a rat.

Jefferson County Public Health said the cat is the first case of plague in the county this year.

Plague is an infectious disease caused by the bacteria Yersinia pestis, and can be contracted by humans and household animals if proper precautions are not taken, JCPH said.

“While plague is a serious disease, and cases of animal-borne disease in household pets is never something we like to see, it is normal and expected for some animals to contract plague in Jefferson County each year,” said Jim Rada, Director of Environmental Health Services at Jefferson County Public Health (JCPH). “The good news is that modern antibiotics are effective against plague, and as long as it is treated promptly, severe complications, illness or death can be avoided.” 

How can the plague be transmitted?

JCPH said humans and pets may be infected with plague by the following ways:

  • Bites from infected fleas
  • By the cough from an infected animal
  • By direct contact with blood or tissues of infected animals.

According to JCPH, both cats and dogs may also come into contact with plague through ingestion of a rodent or by picking up and carrying infected or deceased rodents in their mouth. Cats are more susceptible to plague and may die if not treated promptly with antibiotics. While dogs are not as susceptible, they can be infected.  


  • Sudden onset of high fever
  • Chills
  • Headache
  • Nausea
  • Extreme pain and swelling of lymph nodes, occurring two to seven days after exposure.

“The bottom line is people — and their pets — should avoid contact with any species of wild rodent, especially ones that are sick, dying or already dead,” Rada said. “We know that pets can be unpredictable, but there are things pet owners can do to keep their four-legged family members safe, especially when they live close to rodent populations such as prairie dog colonies.” 

JCPH recommends the following precautions be taken to protect yourself and your pets from the plague. The risk for contracting plague is extremely low if precautions are taken. 

  • Eliminate all sources of food, shelter and access for wild animals around the home. 
  • Do not feed wild animals. 
  • Maintain a litter and trash-free yard to reduce wild animal habitats. 
  • Avoid contact with sick or dead wild animals and rodents. 
  • Use precaution when handling sick pets. Have sick pets examined by a veterinarian. 
  • Consult with your veterinarian about flea and tick control for your pets. 
  • Keep pets from roaming freely outside the home where they may prey on wild animals and bring the disease home with them.  
  • Do not let dogs off leash in the wild or in parks and open spaces.  
  • Whenever possible, keep cats indoors and do not let them free-roam the neighborhood.