The Atlantic Prion diseases are poorly understood, and this one is devastating. Scott Napper, a biochemist and vaccinologist at the University of Saskatchewan, can easily envision humanity’s ultimate doomsday disease. The scourge would spread fast, but the progression of illness would be slow and subtle. With no immunity, treatments, or vaccines to halt its progress, the disease would eventually find just about every single one of us, spreading via all manner of body fluids. In time, it would kill everyone it infected. Even our food and drink would not be safe, because the infectious agent would be hardy enough to survive common disinfectants and the heat of cooking; it would be pervasive enough to infest our livestock and our crops. “Imagine if consuming a plant could cause a fatal, untreatable neurodegenerative disorder,” Napper told me. “Any food grown within North America would be potentially deadly to humans.” This nightmare illness doesn’t yet exist. But for inspiration, Napper needs to look only at the very real contagion in his own lab: chronic wasting disease (CWD), a highly lethal, highly contagious neurodegenerative disease that is devastating North America’s deer, elk, and other cervids.
In the half century since it was discovered in a captive deer colony in Colorado, CWD has worked its way into more than 30 U.S. states and four Canadian provinces, as well as South Korea and several countries in Europe. In some captive herds, the disease has been detected in more than 90 percent of individuals; in the wild, Debbie McKenzie, a biologist at the University of Alberta, told me, “we have areas now where more than 50 percent of the bucks are infected.” And CWD kills indiscriminately, gnawing away at deer’s brains until the tissue is riddled with holes. “The disease is out of control,” Dalia Abdelaziz, a biochemist at the University of Calgary, told me.