Part of what made mad cow disease (bovine spongiform encephalopathy, or BSE) such an insidious health problem was its slow creep. Some epidemiologists are growing concerned about another epidemic caused by prions that has been gathering steam for decades: chronic wasting disease (CWD), an illness like mad cow disease but found primarily in wild populations of elk and deer. The differences between it and mad cow disease are important but so, too, are the parallels. I spoke about this with my science communications pal Jay Ingram, who wrote about the spread of CWD in his most recent book is Fatal Flaws: How a Misfolded Protein Baffled Scientists and Changed the Way We Look at the Brain (HarperCollins 2012). Read more about it in my column for SmartPlanet "The slow march of chronic wasting disease."