A Chaffee County, CO resident has contracted and recovered from bubonic plague being the second human plague case in a month in the state. According to Chaffee County health officials, the state lab confirmed plague (Yersinia pestis) in the individual 10 days ago.

Oriental rat flea, Xenopsylla cheopis/CDC

The unnamed patient was hospitalized and has survived following intravenous antibiotic treatment. Investigation revealed that the family dog became ill with symptoms consistent with plaque a few days prior to the onset of illness in the dog’s owner. The dog has recovered and test results from the dog are pending.

One month ago, a Larimer County teen contracted and died from septicemic plague.

Chaffee County Public and Environmental Health is doing surveillance for rodent die-off and has posted warning signs about plague in the vicinity of the Little Rainbow Trailhead off CR 110.

The bacteria that cause plague, Yersinia pestis, maintain their existence in a cycle involving rodents and their fleas. Plague is a cause of die-offs of rodents and rabbits. When these animals die, fleas leave the carcass to find another host, thus spreading the disease. Most human plague cases result from the bites of infected fleas. Less commonly people are infected by direct contact with fluids or tissues from infected animals including pets.

Many types of animals, such as rock squirrels, wood rats, ground squirrels, prairie dogs, chipmunks, mice, voles, and rabbits can be affected by plague. Wild carnivores and domestic pets can become infected by eating other infected animals.  Cats are particularly susceptible to plague.

Symptoms of plague generally include 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, called a bubo, in the area of the flea bite. If the patient is not promptly treated with antibiotics, the plague bacterium can enter the bloodstream (septicemic plague) or lungs (pneumonic plague) causing severe, life-threatening complications. In rare instances people can inhale the bacterium and initially present with pneumonic plague.

There has been 18 confirmed human plague cases in Colorado since 2005.

LISTEN: Public Health Veterinarian and plague expert discusses plague in the US

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