Abstract
This study developed a method for extracting infectious prions from Class B biosolids and subsequently evaluated the survival of infectious prions under the influence of mesophilic (37°C) and thermophilic (60°C) temperatures in Class B biosolids. Unlike other studies, this study utilized a scrapie cell assay to determine infectivity and quantity of infectious prions. The best method for extraction was exposing the biosolids to 4 M urea at 80°C for 10 minutes followed by a membrane centrifugation to reduce the concentration of urea. The recovery efficiency of the infectious prions from the biosolids for this method was 17.2%. In the survival study, a 2.43-log10 reduction in prion infectivity was observed under mesophilic temperatures after 15 days and a 3.41-log10 reduction after 10 days under thermophilic conditions. The reduction of infectious prions was greater in the biosolids than the control in phosphate buffered saline, suggesting factors other than temperature were also playing a role in the loss of infectivity of the prions in the biosolids.
Acknowledgments
The authors of this work would like to thank the University of Arizona's Technology Research Initiative Fund (TRIF) and the University of Arizona National Science Foundation, Water and Environmental Technology Center for supporting this work. We would also like to thank Drs. Charles Weissmann and Suhkvir Mahal at the Scripps Research Institute for the gift of CAD-2A2D5 cells, RML infected mouse brain homogenate, and their help with providing crucial information for the standard scrapie cell assay.