The pneumonic plague has killed an unidentified person living in Arizona, according to health officials cited in several reports.

The person, who lived in Coconino County, is the first human to die of the disease in that area in close to 20 years, dating back to 2007.

Health officials are telling local residents not to worry given that the diease is treatable with antibiotics.

Less than 10 people on average are diagnosed with the disease in the U.S. each year.

The diease is mostly found in rural areas of northern Arizona, western Nevada, northern New Mexico, southern Colorado, California, southern Oregon, according to the U.S. Centers for Disease Control and Prevention.