An Arizona resident has died from the “most serious” form of the plague, health officials said. The person tested positive for pneumonic plague July 11 in Coconino County, the Health and Human Services Department said in a news release. Pneumonic plague is a “severe lung infection caused by the Yersinia pestis bacterium,” health officials said.

Officials confirmed one person died of pneumonic plague just days after a prairie dog die-off believed to be related to plague.

The patient had arrived at Flagstaff Medical Center and died in the emergency room. It is the first known plague-related death in Coconino County since 2007.