The Colorado Department of Public Health and Environment laboratory identified pneumonic plague in a Colorado resident earlier this week. Investigation revealed the family dog had recently died unexpectedly. The carcass was recovered and tested at the Colorado State University Veterinarian Diagnostic Laboratory, where tests were positive for plague.


Tri-County Health Department officials and the Colorado Department of Public Health and Environment are working together to investigate the source of exposure and to identify those who may have been exposed through close contact with the individual. Any individuals exposed will be recommended for antibiotic treatment.

The patient and the dog may have been exposed in eastern Adams County. Plague is spread from fleas on rodents, most commonly prairie dogs. People walking in open spaces and trails should avoid contact with rodents.

Pneumonic plague is probably the most serious form of plague and it’s when the bacteria infect the lungs and cause pneumonia. It is contracted when the bacteria is inhaled (primary) or develops when bubonic or septicemic plague spreads to the lungs.

Pneumonic plague is contagious and can be transmitted person to person. It is highly communicable under appropriate climate conditions, overcrowding and cool temperatures. Untreated pneumonic plague is frequently fatal. For more infectious disease news and information, visit and “like” the Infectious Disease News Facebook page

Dr. Jennifer House, public health veterinarian at the Colorado Department of Public Health and Environment, encourages people take the following precautions to prevent plague exposure:
  • Do not directly handle any dead rodents.
  • Keep pets away from wildlife, especially dead rodents.
  • Don’t let dogs or cats hunt prairie dogs or other rodents.
  • Don’t allow pets to roam freely.
  • Treat all pets for fleas according to a veterinarian’s advice.
  • Do not feed prairie dogs or other rodents – this attracts them to your property, brings them in close contact with other rodents and increases the risk of disease transmission.
  • Be aware of rodent populations in your area and report sudden die-offs or multiple dead animals to your local health department.
Contact your physician if you develop a high fever and other plague symptoms following a fleabite or direct contact with dead rodents. Symptoms of plague include a sudden onset of high fever, muscle pain, malaise, nausea and vomiting, or a general feeling of being ill. Individuals with bubonic plague will develop a large, swollen, painful lymph node in the area of a flea bite, usually in the groin or armpit. If untreated, the disease can enter the bloodstream or lungs, which are severe, life-threatening complications. Individuals with pneumonic plagues (the lung form) develop fever, headache, weakness, shortness of breath, chest pain, cough which can lead to respiratory failure.
 Since 1957, Colorado has identified 60 cases of human plague, nine (15 percent) of which were fatal.