Key TakeawaysPneumonic plague is the rarest and deadliest form of plagueA person in northern Arizona has died from the infection, health officials saidPlague is spread by infected fleas or contact with sick animals.MONDAY, July 14, 2025 (HealthDay News) — An Arizona resident has died from pneumonic plague, a rare but serious illness, health officials confirmed.The death happened in Coconino County in Northern Arizona, which includes Flagstaff. Officials gave no information about the person who died, the Associated Press reported.This is the first known U.S. death from pneumonic plague since 2007, according to local and federal health officials. If caught early, pneumonic plague can usually be treated successfully with antibiotics.Plague is a bacterial infection that spreads mainly in the western United States.On average, about seven human cases are reported each year nationwide, the U.S. Centers for Disease Control and Prevention (CDC) says.Plague is caused by a bacterium called Yersinia pestis. It claimed millions of lives in 14th century Europe.The most common form is bubonic plague, which is commonly spread among rodents like prairie dogs and rats, according to the AP.But there are two other types: Septicemic plague, which spreads throughout the body, and pneumonic plague, which infects the lungs.Pneumonic plague, which caused the Arizona death, is also the easiest to spread, the AP said.It is often transmitted by fleas that have bitten infected rodents. The fleas can also infect pets or humans.People can also get plague from touching blood or body fluids from infected animals. That’s why health experts warn against handling sick or dead animals.Most U.S. cases happen in rural areas of northern Arizona, northern New Mexico, southern Colorado, California, southern Oregon and far western Nevada, the AP said.More informationThe Cleveland Clinic has more on plague.SOURCE: The Associated Press, July 11, 2025.What This Means For YouPlague is very rare but it still exists. People living in the western U.S. should avoid contact with sick or dead animals..Sign up for our weekly HealthDay newsletter