In a shocking diagnosis, it has been determined a seven-year-old Colorado girl has the bubonic plague, in the state’s first case of the archaic illness since 2006.

Doctors believe Sierra Jane Downing became stricken with the disease after coming in contact with a dead squirrel while camping with her family in Pagosa Springs.

The bubonic plague, also known as the “black death,” is often transmitted by fleas.

The girl’s parents rushed her to the Rocky Mountain Hospital for Children, where she was then flown via helicopter to Presbyterian St Luke’s Medical Center in Denver.

“She originally presented with a temperature of 107 degrees,” said Dr Wendi Drummond. “She had also had a seizure.”

Doctors initially thought it was a case of septic shock, but after running numerous tests, they diagnosed the plague, something they had never seen before in practice.

The plague hasn’t been recorded by the Colorado Department of Public Health and Environment since 2006.

Without treatment the plague kills around two thirds of infected humans within four days.

“It’s one of those things that you don’t necessarily expect to see,” Dr Drummond said. “But, it’s definitely one of those things you don’t want to miss.”

Elite.