Lethal Weapon

Soils may harbor a surprising prion killer.

SCIENTISTS HAVE TRIED ABOUT EVERYTHING TO KILL PRIONS, the pernicious pathogens that are believed to cause chronic wasting disease and a host of other fatal brain diseases. Fire doesn’t work. Nor do radiation, chemicals or autoclaving, all of which reduce the infectivity of prions but fail to completely eliminate them.

But Joel Pedersen, a CALS professor of soil science and environmental chemistry, may have uncovered a surprising new weapon against prions-and it’s been underneath our feet all along. Pedersen and his collaborators have found that birnessite, a common mineral found in soils, can penetrate prions and degrade the proteins, offering a hopeful new strategy for decontaminating prion-infected soils.

Previous studies have shown that prions can survive in soil for at least three years. It is likely that these prion reservoirs play a critical role in spreading the pathogen among animals. “We know that environmental contamination occurs in deer and sheep at least,” Pedersen says.

Birnessite, an oxidized form of manganese found in poorly drained soils, is among the most powerful oxidants in nature, says Pedersen. But while the mineral degrades prions in solution, the team has yet to test whether it can do the same to prions in soils. If it can, birnessite may become a useful tool for cleaning prion-infected soils in barnyards and the wild. “I expect that its efficacy would be somewhat diminished in soil,” says Pedersen. “It’s something we’ll explore.”