The state of Colorado has reported their fifth case of plague in 2014 in a La Plata County resident, according to the San Juan Basin Health Department (SJBH). County health officials in coordination with the Colorado Department of Public Health and Environment (CDPHE)  identified a case of bubonic plague Friday.

This is the first case of of bubonic plague in the La Plata County since 2006. Four other cases of human plague have been identified this year in Adams County.

This image depicts a magnified view of an oriental rat flea, Xenopsylla cheopis. Image/CDC
This image depicts a magnified view of an oriental rat flea, Xenopsylla cheopis. Image/CDC

The female patient has been treated with antibiotics and released from the hospital. SJBH is investigating possible sources of plague exposure for the case.

Plague is an infectious disease caused by the bacterium, Yersinia pestis. It is found in animals throughout the world, most commonly rats but other rodents like ground squirrels, prairie dogs, chipmunks, rabbits and voles. Fleas typically serve as the vector of plague. Human cases have been linked to the domestic cats and dogs that brought infected fleas into the house.

People can also get infected through direct contact with an infected animal, through inhalation and in the case of pneumonic plague, person to person.

Yersinia pestis is treatable with antibiotics if started early enough.

There are three forms of human plague; bubonic, septicemic and pneumonic.

Bubonic plague: This is the most common form. In this form, the bacteria enter the body through the bite of an infected flea or rodent. Here the bacteria infect the lymphatic system. After a few days to week, the person will experience fever, chills, weakness, and swollen lymph glands. These are called buboes.

In the U.S., bubonic plague is sporadic, primarily in the West. Typically, there are around 10 cases annually in this country.

Untreated bubonic plague is fatal about half the time. For more infectious disease news and information, visit and “like” the Infectious Disease News Facebook page.

Septicemic plague: This form is also contracted from a flea or rodent bite. Sometimes it appears subsequent to untreated bubonic or pneumonic plague. It involves bloodstream dissemination to all areas of the body. Buboes do not occur. Symptoms are endotoxic shock and disseminated intravascular coagulation. Untreated septicemic plague is nearly always fatal.

Pneumonic plague: 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.

Related article: The US ranks 11th in human plague cases worldwide during the last decade

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.

SJBH says Colorado has had a total of 64 cases of human plague, nine (14 %) of which were fatal, since 1957.