October 18, 2012 2:34 pm
Brain-Eating Crows May Help Spread Prion Diseases
Scavenging crow. Photo: emersonquinn
Prions—the infectious proteins that cause illnesses such as mad cow disease, scrapie, chronic wasting disease and Creutzfeldt-Jakob disease—can pass through the digestive systems of crows, new research published in PLoS One finds. The crows are unharmed during the process, and scientists suspect that the birds may play a part in transmitting prion diseases from one location to another, one animal (or, eventually, human) to the next.
To make this discovery, the researchers fed crows prion-infected mice brains. When the crows excreted the digested brains around four hours later, the prions emerged without any damage. The researchers then injected healthy mice with prions recovered from the crows’ droppings, and those mice showed signs of prion disease.
Crows are likely not alone in their passive role as prion transmitters. Other studies suggest that insects, poultry and other scavengers may passively carry prions without showing any disease symptoms themselves. But this study is the first to demonstrate that those consumed prions can retain their ability to cause disease even after being digested. When it comes to prion diseases, Poe may have been right to dub the “grim, ungainly, ghastly, gaunt” raven an ominous “thing of evil” tossed by tempest onto horror-haunted homes.
More from Smithsonian.com:
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One Smart Crow
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Hel anyone who plays resident evil knows that crows are the first thing you watch out for, but at the same time this article may cause anyone with a gun and no brains to start murdering murders just so they feel safe. (murders are flocks of crows for those who don’t know
Comment by Henry Valdez — October 19, 2012 @ 7:10 pm
This blog post and its rather inflammatory ending statement is just plain irresponsible. There is so much misinformation on crows that to act as if they have now been demonstrated as major transmitter of prion diseases is just a layman-type twisting of facts and conclusions. The science demonstrated that prions can make it through the avian digestive tract. Crows make migratory movements and scavenge. OK. There are so many other routes to moving prion diseases. Coyotes, foxes, dogs, vultures…hey, what about vultures? They are migratory and form big roosts. And what about sewage sludge? Humans are almost certainly capable of transmitting prions through their digestive tracts. Crows eat more insects than mice. They cannot break into the brains of dead deer without help. Come on…let’s get this story straight.
This article and the media have simply managed to pick up the indestructible prion of “black crows/ravens are evil!”. And Smithsonian of all places is now spreading it. I had expected better of Smithsonian and its associated bloggers.
Comment by Anne Clark — February 19, 2013 @ 7:27 am