Associated Press
Grand Canyon National Park biologist Eric York had done a necropsy on a mountain lion a few days before his death. The big cat also died of the plague.

PHOENIX (AP) — Tests done by federal health officials have confirmed that a wildlife biologist at Grand Canyon National Park died from the plague.

Eric York, 37, died Nov. 2 in his home at the Grand Canyon. He had done a necropsy on a mountain lion a few days earlier, and tests on the big cat show it too had died of the plague.

National Park Service officials suspected plague after York died and began precautionary antibiotic treatment of nearly 50 people in the days following his death. None became ill.

Preliminary tests released last week were positive for the disease, and final results released Nov. 16 confirmed York died of plague.

The federal Centers for Disease Control and Prevention found that York had the identical strain of the bacterial disease as the dead cougar.

York, whose family lives in Massachusetts, had worked in the Grand Canyon for two years. He had worked previously for state parks in California and had traveled to Nepal, Chile and Pakistan to work with protected animals.

Health officials in Arizona warned in September that the plague appeared to be on the rise and that more cases were likely after an Apache County woman survived an infection with the disease.

That case, the first human infection reported in Arizona since 2000, followed the discovery of an outbreak of the disease in prairie dogs in Flagstaff in August.

Arizona health officials have been wary about a plague outbreak because of greater activity in New Mexico and other nearby states in the past year. In New Mexico, the plague caused the death of a 3-year-old boy in June. The disease is endemic to the Southwest.

An average of 13 plague cases are reported in the United States each year. Fourteen percent of cases are fatal, according to the Centers for Disease Control and Prevention.

While Arizona health officials say the disease appears to be on the rise in the state, CDC officials said plague cases weren't increasing this year on a national level.

Plague is transmitted primarily by fleas and direct contact with infected animals. When the disease causes pneumonia, it can be transmitted from an infected person to a non-infected person by airborne cough droplets. Cases are treatable with antibiotics, but the CDC reports that up to 50 percent are fatal if the disease causes pneumonia.