Beware the Shape-shifter:
"If CWD were to transmit to humans, we don't know whether it would look like new variant CJD. It could have an entirely different neuropathology and not exclusively affect younger people," Telling says.
U.S. doctors and scientists are looking for CJD more closely than before, he says, but it's a difficult task. "CJD is a rare disease, and it can look a lot like other neurological disorders. It's only definitively diagnosed with a brain biopsy after death."
Telling talks about the much publicized group of Wisconsin hunters who annually feasted on wild game, including elk from Colorado and deer from Wisconsin. Two of the men died in 1993 and the third in 1999; all were between the ages of 55 and 60. All appeared to have CJD and, because of the shear numeric improbability that this was coincidence, speculation ran rampant that they got the disease from consuming prion-infected meat. "Tests have proven that one of them died from Pick's Disease, a related, non-prion neurological disorder. One of them had an inherited form of prion disease caused by a mutation." The third man's disease could not be scientifically linked to CWD, Telling says.
"Right now there's no convincing evidence that any of these cases in the United States acquired CJD as a result of being exposed to either BSE or CWD prions, but people tend to make those connections easily. Because the stakes are very high, it's important not to jump to premature conclusions."
Telling is seeking $2.6 million from the Department of Defense for his next study in collaboration with colleagues at the University of Rochester in New York. This study is related to work by Adriano Aguzzi, a pathologist in Zurich, who has made transgenic mice that express a particular antibody and are completely resistant to prion infection.
"His results give evidence that immunotherapy for prions is a possibility," Telling says. "We'll test specific antibodies produced at the University of Rochester to see if those antibodies can protect against the development of CWD using our transgenic models. Immunotherapy is one of the hottest topics in prion research right now."
This $2.6 million is part of a $42.5 million congressional appropriation to the National Prion Research Program, run by the DoD. The military is supporting prion research based on the potential threat to food and blood supplies.
"By being proactive the U.S. government is taking exactly the right approach," Telling says. "CWD is an emerging disease, perhaps the least understood of all of the prion diseases in animals. It's extremely contagious, and it's an open question whether it's going to be a major public health threat or transmit to other animals.
"There are still a lot of unknowns, and it's critical to keep an open mind. It's important to err on the side of caution, in light of the debacle that occurred in the U.K."
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