title: An assessment of the long-term persistence of prion infectivity in aquatic environments.
abstract: The environment plays a key role in horizontal transmission of prion diseases, since prions are extremely resistant to classical inactivation procedures. In prior work, we observed the high stability of bovine spongiform encephalopathy (BSE) infectivity when these prions were incubated in aqueous media such as phosphate-buffered saline (PBS) or wastewater for nearly nine months. As a continuation of this experiment, the same samples were maintained in PBS or wastewater for five additional years and residual BSE infectivity was assessed in bovine PrPCtransgenic mice. Over this long time period (more than six years), BSE infectivity was reduced by three and one orders of magnitude in wastewater and PBS respectively. To rule out a possible agent specific effect, sheep scrapie prions were subjected to the same experimental protocol, using eight years as the experimental end-point. No significant reduction in scrapie infectivity was observed over the first nine months of wastewater incubation while PBS incubation for eight years only produced a two logarithmic unit reduction in infectivity. By contrast, the dynamics of PrPRespersistence was different, disappearing progressively over the first year. The long persistence of prion infectivity observed in this study for two different agents provides supporting evidence of the assumed high stability of these agents in aquatic environments and that environmental processes or conventional wastewater treatments with low retention times would have little impact on prion infectivity. These results could have great repercussions in terms of risk assessment and safety for animals and human populations.
authors: Centro de Investigación en Sanidad Animal, CISA-INIA, Carretera Algete-El Casar S/n, Valdeolmos, 28130 Madrid, Spain.
authors: Alba
authors: A
authors: Marín-Moreno
authors: Centro de Investigación en Sanidad Animal, CISA-INIA, Carretera Algete-El Casar S/n, Valdeolmos, 28130 Madrid, Spain.
authors: Juan-Carlos
authors: JC
authors: Espinosa
authors: Centro de Investigación en Sanidad Animal, CISA-INIA, Carretera Algete-El Casar S/n, Valdeolmos, 28130 Madrid, Spain.
authors: Natalia
authors: N
authors: Fernández-Borges
authors: Centro de Investigación en Sanidad Animal, CISA-INIA, Carretera Algete-El Casar S/n, Valdeolmos, 28130 Madrid, Spain.
authors: Juan
authors: J
authors: Píquer
authors: Department of Microbiology, University of Barcelona, Diagonal 643, 08028 Barcelona, Spain.
authors: Rosina
authors: R
authors: Girones
authors: UMR INRA-ENVT 1225, Interactions Hôte Agent Pathogène, Ecole Nationale Vétérinaire de Toulouse, Toulouse, France.
authors: Olivier
authors: O
authors: Andreoletti
authors: Centro de Investigación en Sanidad Animal, CISA-INIA, Carretera Algete-El Casar S/n, Valdeolmos, 28130 Madrid, Spain. Electronic address: jmtorres@inia.es.
authors: Juan-María
authors: JM
authors: Torres
mesh_terms: D000818:Animals; D001681:Biological Assay; D002417:Cattle; D016643:Encephalopathy, Bovine Spongiform / Q000635:transmission*; D008822:Mice, Transgenic; D010710:Phosphates / Q000737:chemistry*; D011328:Prions / Q000032:analysis / Q000235:genetics / Q000472:pathogenicity*; D012608:Scrapie / Q000635:transmission*; D012756:Sheep; D013997:Time Factors; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods
chemical_list: D010710:Phosphates; D011328:Prions; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: BSE; Infectivity; Prion; Scrapie; Wastewater