If You See a Cow, Hold Your Breath

If you thought that not eating beef was a sure-fire way of avoiding mad cow disease, think again. A new study — conducted by researchers in Switzerland and Germany, and published this week in PLoS Pathogens — shows that prions, the misshaped proteins that cause brain degenerating diseases like mad cow and Creutzfeldt–Jakob disease, can be spread through the air, reports New Scientist's Debora MacKenzie. The researchers exposed mice to aerosols containing as little as 2.5 percent brain tissue from mice with the animal prion disease scrapie. All it took was an exposure of 10 minutes for the healthy mice to become infected, the researchers report. "This doesn't mean animals or people with prion diseases actually transmit them through the air: there have been no unexplained cases of disease transmission which suggested this," MacKenzie says. "But workers in mills that process potentially infected carcasses may need more respiratory protection." Labs working with prions may also need to rethink their safety measures, she adds.