title: Persistence of the bovine spongiform encephalopathy infectious agent in sewage.
abstract: Horizontal transmission of prion diseases through the environment represents a considerable concern. Prions are extremely resistant to inactivation and are thought to enter the environment after burial of animal mortalities or through biosolids from wastewater treatment plants. In addition, deposition of prions in the environment through biological fluids and/or faeces has been proved in the last years. Little is known about the behaviour of prion infectivity in the environment. In this study, the persistence of BSE infectious agent in sewage has been assessed by both PrP(Res) immunoblotting and mouse bioassay in a long-term incubation study. Results indicated that no PrP(Res) was detected after 150 day of incubation and consistent with this, a statistical regression model estimated 2-logs decay in 151 day. In contrast, no reduction in infectivity was observed during this period. Similarly, BSE infectivity remained unaltered after incubation in PBS for 265 day, whereas PrP(Res) levels dropped progressively over the length of the study. These results indicate that in sewage and PBS, prion infectivity persists longer and with different dynamics than its commonly used marker PrP(Res). Thus, mathematical models computed on the basis of PrP(Res) detection were unable to predict inactivation of prion infectivity. It is also reasonable to assume that conventional wastewater treatments with low retention times could have a very limited impact on prion infectivity. This data is essential for the development of accurate risk assessment analysis for BSE and other prion diseases in the environment.
authors: Department of Microbiology, University of Barcelona, Diagonal 643, 08028 Barcelona, Spain.
authors: Carlos
authors: C
authors: Maluquer de Motes
authors: Juan-Carlos
authors: JC
authors: Espinosa
authors: Ana
authors: A
authors: Esteban
authors: Miquel
authors: M
authors: Calvo
authors: Rosina
authors: R
authors: Girones
authors: Juan María
authors: JM
authors: Torres
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods; D002417:Cattle; D016643:Encephalopathy, Bovine Spongiform / Q000635:transmission*; D015151:Immunoblotting; D051379:Mice; D008954:Models, Biological; D011328:Prions / Q000032:analysis* / Q000472:pathogenicity*; D012044:Regression Analysis; D018570:Risk Assessment; D012722:Sewage / Q000737:chemistry*; D013030:Spain; D013997:Time Factors
chemical_list: D011328:Prions; D012722:Sewage