Beware the Shape-shifter
U.S. faces "made cow-like" epidemic in deer and elk
First it killed sheep. Then it ate cannibals. In the past 10 years, it's created thousands of "mad cows" and warped a rare, age-related brain disease into a death sentence for teenagers who ate British burgers. And today, roaming the wide-open plains of the American West are emaciated deer and elk plagued by this incredibly contagious agent.
Its name: prion (pronounced PREE-ahn). Prion proteins naturally exist on the surface of nerve cells in the brain of every human and animal. In most of us this protein never reveals its mongrel potential, but when it does shape-shift into a fiend, it is inevitably fatal.
Glenn Telling at the University of Kentucky is facing this monster head-on in his current research to study chronic wasting disease, the prion protein's deer and elk killer. With grants from the National Institutes of Health, Telling is using basic science to shed some light on the least understood of the prion diseases in animals and trying to answer the question of whether CWD, following mad cow's precedent, could spawn a disease that targets humans.
Sheep and Cannibals
Three hundred years ago a Scottish farmer noticed something odd in his sheep and goats. They were scraping off their wool and hair by rubbing themselves against stone walls, fence posts, anything they could find, as if they were scratching at an itch they couldn't quite reach. Mysteriously, these animals soon suffered premature deaths.
This condition, dubbed scrapie, remained little more than a veterinary curiosity until the advent of a disease called kuru, recognized in the 1950s in a remote cannibalistic tribe, the Fore people in Papua New Guinea. Part of their funeral rituals involved cooking and eating the brains of dead tribe members, but beyond being gruesome, this ritual was killing the Fore.
Carleton Gajdusek, who received the 1976 Nobel Prize for his kuru research, discovered the time from first symptom to death was three to 12 months. In 1959, research veterinarian William Hadlow pointed out the remarkable similarities between scrapie and kuru, namely the destruction of brain tissue characterized by sponge-like holes.
This appearance of brain tissue destroyed by what was later identified as prions led researchers to dub this family of fatal diseases "transmissible spongiform encephalopathies."
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