Officials from Grand Canyon National Park announced on Friday that Eric York, a 37-year-old wildlife biologist for the National Park Service, died of plague after being misdiagnosed with flu. Apparently he got Yersinia pestis during an autopsy of a mountain lion (cougar) on Oct. 27.

Three days later, on Oct. 30, he showed up at the Grand Canyon Clinic, located on the South Rim of the Grand Canyon, with flu-like symptoms and was diagnosed as such and sent home. He was found dead in his home on Nov. 2 and his autopsy showed infection with Yersinia pestis, the Gram-negative bacillus bacterium which causes bubonic plague.

Grand Canyon National Park spokeswoman Pamela Walls said 49 people, including co-workers and roommates but no park visitors, are known to have had contact with York, and they have been put on antibiotics, but none has shown symptoms of the disease.

York worked in the park's cougar collaring program. During the Oct. 27 necropsy of a cougar which had died from the plague, he was exposed to its internal organs.

This is a highly unusual way of getting infected. Normally, infection in humans occurs when a person is bitten by a flea that has been infected by biting a rodent that itself has been infected by the bite of a flea carrying the disease.

The pneumonic plague has initial symptoms such as headache, weakness, and coughing with hemoptysis, which are virtually indistinguishable from other respiratory illnesses. However, unlike flu, lung infection with Yersinia pestis can be fatal in one to six days and mortality in untreated cases is more than 50 percent.