Prion research helps prevent BSE

BSE shook the livestock industry when it showed up in a cow eleven years ago. The disease did not remain in Canada’s herd but work to prevent it intensified.

BSE is a prion disease. Prions are a problematic protein associated with BSE in cattle, chronic wasting disease in deer and elk and scrapie in sheep. Work at Agriculture and Agri-Food Canada’s Lethbridge Research Centre has helped make Canada a leader in prion science.

For seven years Tim McAllister and his team at the Lethbridge Research Centre examined what composting does to prions that cause BSE. They studied them in compost in an indoor containment area as well as outdoors.
“Within the containment area, about 99 percent of the prions were degraded as a result of the composting process,” McAllister said. “When we did the larger scale composting here it was much higher than that, probably less than .01 percent of the prions were still viable after that period of time.”

He also found that mixing the manure with chicken feathers, as a source of keratin to enrich the microbial levels in the compost, further enhances degradation of the prions.

“It certainly puts some science that prions are in fact not stable in the environment forever, that there are means of degredating them using biological approaches such as composting,” said McAllister.

The research also explored chronic wasting disease prion’s potential for uptake and transmission by plants. If they do, could plants transmit CWD among wild deer and elk.

Researcher Jay Rasmussen said, “It looks like it isn’t occuring to a large extent, like there isn’t a large accumulation of protein in the plant but further studies probably need to be done in order to determine definitively is there is a lower level that actually is transported.”

The research centre’s work shows composting degrades prions that cause BSE and and other prion diseases however it is not the regulatory body that approves or disapproves their use. McAllister says that will be up to the Canadian Food Inspection Agency.

In addition, a recent animal infectivity study between McAllister’s group and the CFIA showed that proper composting reduces the infectivity of prions to the point where they no longer present a significant disease risk.