Air Date: Week of September 27, 2002

Living on Earth’s Jessica Penney reports on new research into preventing mad cow disease.

Transcript

CURWOOD: Just ahead, the first study in humans to connect sex-linked behaviors to prenatal exposure to dioxin and PCB’s. First, this environmental health note from Jessica Penney.

[THEME MUSIC]

PENNEY: There may be encouraging news on the horizon for meat-eaters. Researchers say it may be possible to breed animals resistant to diseases like mad cow disease, scrapie in sheep and chronic wasting disease in deer and elk. Infectious proteins called prions cause these illnesses. And when a prion comes in contact with a healthy protein in an animal’s brain, it can infect the healthy protein and start a chain reaction. Eventually, brain cells die.

People eating infected animals run the risk of contracting the illness themselves. It’s known that some breeds of sheep don’t get scrapie. It’s thought that these sheep are resistant because of a mutation found in their brain proteins that enables the protein to resist being turned into a prion.

Researchers at the University of California in San Francisco have confirmed the theory by genetically engineering mice to produce protein with the same mutations. When the scientists injected prions directly into the brains of these mice, they did not get sick. So the researchers think it may be possible to confirm which animals naturally have this useful mutation. At that point, traditional breeding methods could be used to produce livestock resistant to prion diseases. That’s this week’s Health Note. I’m Jessica Penney.

CURWOOD: And you’re listening to Living on Earth.

[MUSIC: Pell Mell, "Nothing Lies Still Long" INTERSTATE (Geffen Records, 1995)]