Sludge Watch ==> Study: Sewage sludge may be route to convey prion diseases

[Maureen Reilly]

http://www.prion2007.com/pdf/Prion%20Book%20of%20Abstracts.pdf

P04.61
Survival of PrPSc during Simulated Wastewater Treatment Processes
Pedersen, J1 ; Hinckley, G1 ; McMahon, K2 ; McKenzie, D3 ; Aiken, JM3
1
University of Wisconsin, Soil Science/Civil and Environmental Engineering, 
USA;
2
University of Wisconsin, Civil and Environmental Engineering, USA;
3
University of
Wisconsin, Comparative Biosciences, USA

Concern has been expressed that prions could enter wastewater treatment 
systems
through sewer and/or septic systems (e.g., necropsy laboratories, rural meat
processors, private game dressing) or through leachate from landfills that 
have
received TSE-contaminated material.

Prions are highly resistant to degradation and
many disinfection procedures raising concern that they could survive 
conventional
wastewater treatment. Here, we report the results of experiments examining 
the
partitioning and survival of PrPSc during simulated wastewater treatment 
processes
including activated and mesophilic anaerobic sludge digestion.

We establish that PrPSc
can be efficiently extracted from activated and anaerobic digester sludges 
with 1%
sodium dodecyl sulfate, 10% sodium undecyl sulfate, and 1% sodium N-lauryl
sarcosinate. Activated sludge digestion does not result in significant 
degradation of
PrPSc .

The protein partitions strongly to the activated sludge solids and is 
expected to
enter biosolids treatment processes. A large fraction of PrPSc survived 
simulated
mesophilic anaerobic sludge digestion. Our results suggest that if prions 
were to enter
municipal waste water treatment systems, most of the agent would partition 
to
activated sludge solids, survive mesophilic anaerobic digestion, and be 
present in
treated biosolids.

Land application of biosolids containing prions could represent a
route for their unintentional introduction into the environment. Our results 
argue for
excluding inputs of prions to municipal wastewater treatment facilities that 
would result
in unacceptable risk of prion disease transmission via contaminated 
biosolids.


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REMINDER OF PRIOR PEDERSEN RESEARCH:  (Al Rubin wrote to this guy and tried 
to yank his chain, influence outcome of research?   I don't think Al got 
what he wanted ! )

http://www.jsonline.com/story/index.aspx?id=631364

Dirt boosts prion disease, study says
Findings affirm chronic wasting's longevity in soil
By BRANDY BENEDICT
bbenedict at journalsentinel.com
Posted: July 10, 2007
Prions and dirt can make a sickening combination.

Researchers at the University of Wisconsin-Madison found that when prions, 
the abnormal proteins believed to cause chronic wasting disease in deer, are 
bound to common soil minerals, they become nearly 700 times more infectious 
than prions alone.

The study was published Friday in the Public Library of Science journal 
Pathogens.

"We're kind of surprised with the result," said Judd Aiken, senior author of 
the study and professor of comparative biosciences in the University of 
Wisconsin-Madison School of Veterinary Medicine.

In an earlier study, Aiken and his team found that prions bind tightly to 
the minerals - so tightly, in fact, that they had trouble getting them off.

"We expected that the tight binding would decrease the infectivity," Aiken 
said.

Just the opposite, the researchers discovered.

Using very low levels of prions and very small particles of soil, they fed 
prion-laden soil particles to hamsters, recording how many became infected 
and how long it took before they showed symptoms of the disease.

They found that the rodents were nearly 700 times more likely to develop the 
disease, and the time between exposure and the first sign of infection was 
shorter.

"In general, they got sicker quicker," Aiken said.