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You catch flu by inhaling germs – now it seems you can catch prion diseases that way too.

Prions are misshapen proteins that cause brain degeneration in conditions such as mad cow disease and scrapie in animals, and Creutzfeldt–Jakob disease in humans. They can get into you if you eat infected meat or receive infected blood, but it was thought they couldn't spread through air.

Now Adriano Aguzzi of the Swiss Federal Institute of Technology in Zurich reports that mice exposed for 10 minutes to aerosols containing as little as 2.5 per cent brain tissue from mice with scrapie all developed the disease within months. The prions didn't need processing by the immune system first, as some other research has suggested, but entered the brain directly through nasal nerves.

"We were amazed at how efficiently they spread," says Aguzzi. He warns that 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. But workers in mills that process potentially infected carcasses may need more respiratory protection.

This is unsettling, but not surprising news.  Any pathogen that can bypass the formidable healthy human immune system, is something to be quite concerned about.  Prions are incredibly robust protein structures, and can survive extreme environmental conditions. There is no cure for prion disease yet, which is progressive and inevitably fatal, and can be spread from animal to human.  An aerosolized, i. e., weaponized prion weapon would be one of your worst nightmares, as it could take months, years, even decades before its victims became cripplingly symptomatic. And it's a safe bet that prions have been studied very closely for that very reason. To read the rest of the article, click here.