The results of a groundbreaking new study indicate that chronic wasting disease (CWD) in deer and elk may be spread by excreted proteins found in the infected animal’s feces.
The report, published in the September 9 issue of the journal Nature reveals that CWD-symptomatic prions (or modified proteins) are found in the droppings of deer months before clinical symptoms of the disease are seen in the animals, according to the research team, at University of California, San Francisco and the Colorado Division of Wildlife’s Wildlife Research Center.
Deer, elk and moose inadvertently consume feces and soil in the course of their daily grazing. Given this, the team set out to determine whether the animals could develop CWD through long-term consumption of contaminated feces.
Researchers measured the amount of prions contained in the feces of orally infected deer up until the time they became symptomatic and then calculated whether prolonged exposure to the concentrations of prions in these feces would be enough to cause the disease.
“Our findings suggest that prolonged fecal prion excretion by infected deer provides a plausible explanation for the high level of transmission of chronic wasting disease within deer herds, as well as prion transmission among deer and other cervid species. Our work may also explain transmission of scrapie prions among sheep and goats,” says senior author and Nobel laureate Stanley B. Prusiner, MD, UCSF professor of neurology and director of the UCSF Institute for Neurodegenerative Diseases.