Prions (IMAGE) American Chemical Society Caption Wastewater treatment plants do not reduce harmful proteins called prions that cause incurable brain infections, such as Mad Cow disease, scientists report. Credit Courtesy of Katherine McMahon Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.