‘Zombie deer disease’ epidemic spreads in Yellowstone as scientists raise fears it may jump to humans

A mule deer in Yellowstone national park in Wyoming. Chronic wasting disease (CWD) spreads through cervids, which also include elk, moose and caribou. It is always fatal, persists for years in dirt or on surfaces, and is resistant to disinfectants, formaldehyde, radiation and incineration. Photograph: Neal Herbert/NPS

When the mule deer buck died in October, it perished in a place most humans would consider the middle of nowhere, miles from the nearest road. But its last breaths were not taken in an isolated corner of American geography. It succumbed to a long-dreaded disease in the backcountry of Yellowstone national park, north-west Wyoming – the first confirmed case of chronic wasting disease in the country’s most famous nature reserve.

For years, chronic wasting disease (CWD), caused by prions – abnormal, transmissible pathogenic agents – has been spreading stealthily across North America, with concerns voiced primarily by hunters after spotting deer behaving strangely.