Deformed proteins called prions cause fatal brain-destroying disorders, such as chronic wasting disease in deer and elk and mad cow disease, which can infect people. Evidence suggests that prions make their way into animals' nervous systems through ingestion, but scientists aren't sure.
A new study shows that prions become more infectious when they latch on to soil particles that animals eat, suggesting that ingestion is a primary route of disease transmission. "Our study points us in one direction that explains how these animals are getting infected," says study author Judd Aiken of the University of Wisconsin–Madison.
Prions enter the environment from the remains of infecte