Sludge Watch ==> Prions may be more mobile under limed conditions!

[Maureen Reilly]

Toward Safer Disposal Of Animals Infected With Mad Cow And Other Prion 
Diseases

Science Daily: <http://www.sciencedaily.com>

— Burying prion-infected carcasses of cattle, deer and other animals in lime 
may actually enhance the spread of those infectious proteins through soil, a 
new study suggests. Placing quicklime on carcasses once was thought to be 
the best way to foster quick decay of bodies and to prevent the spread of 
disease.




The study is scheduled for the April 15 issue of ACS’ Environmental Science 
& Technology, a semi-monthly journal.

In the study, Joel A. Pedersen and colleagues from the University of 
Wisconsin cite the need for safe methods of disposing of prion-infected 
carcasses, noting that prions can resist harsh conditions such as strong 
disinfectants and dry-heat temperatures of 1,100°F that destroy other 
disease-causing agents and that prions can remain infectious in the soil for 
at least three years. Pedersen and colleagues investigated the effect of 
different conditions (pH, salinity) on the adsorption, or attachment, of 
prions to sand particles.

They found that prions become less firmly attached to sand particles, and 
thus potentially more mobile, under alkaline conditions. These conditions 
would be produced by lime, as well as in older landfills. In the natural 
environment, acidic conditions may keep prions near the soil surface, 
increasing the risk that animals will ingest prions and become infected, the 
report says. The team is conducting further research to determine whether 
these expectations are borne out.

Note: This story has been adapted from a news release issued by American 
Chemical Society.