OATAO - Open Archive Toulouse Archive Ouverte Open Access Week

Prions in Milk from Ewes Incubating Natural Scrapie

Lacroux, Caroline and Simon, Stéphanie and Benestad, Sylvie and Maillet, Séverine and Mathey, Jacinthe and Lugan , Sévérine and Corbière, Fabien and Cassard, Hervé and Costes, Pierrette and Bergonier, Dominique and Weisbecker, Jean-Louis and Moldal, Torffin and Simmons, Hugh and Lantier , Frédéric and Féraudet-Tarisse, Cécile and Morel, Nathalie and Schelcher, François and Grassi, Jacques and Andréoletti, Olivier Prions in Milk from Ewes Incubating Natural Scrapie. (2008) PLoS Pathogens, vol. 4 (n° 12). pp. 1-11. ISSN 1553-7366

[img]
Preview
(Document in English)

PDF - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
2MB

Official URL: http://tinyurl.com/3wly6x

Abstract

Since prion infectivity had never been reported in milk, dairy products originating from transmissible spongiform encephalopathy (TSE)-affected ruminant flocks currently enter unrestricted into the animal and human food chain. However, a recently published study brought the first evidence of the presence of prions in mammary secretions from scrapie-affected ewes. Here we report the detection of consistent levels of infectivity in colostrum and milk from sheep incubating natural scrapie, several months prior to clinical onset. Additionally, abnormal PrP was detected, by immunohistochemistry and PET blot, in lacteal ducts and mammary acini. This PrPSc accumulation was detected only in ewes harbouring mammary ectopic lymphoid follicles that developed consequent to Maedi lentivirus infection. However, bioassay revealed that prion infectivity was present in milk and colostrum, not only from ewes with such lymphoproliferative chronic mastitis, but also from those displaying lesion-free mammary glands. In milk and colostrum, infectivity could be recovered in the cellular, cream, and casein-whey fractions. In our samples, using a Tg 338 mouse model, the highest per ml infectious titre measured was found to be equivalent to that contained in 6 mg of a posterior brain stem from a terminally scrapie-affected ewe. These findings indicate that both colostrum and milk from small ruminants incubating TSE could contribute to the animal TSE transmission process, either directly or through the presence of milk-derived material in animal feedstuffs. It also raises some concern with regard to the risk to humans of TSE exposure associated with milk products from ovine and other TSE-susceptible dairy species.

Item Type:Article
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Institut National de la Recherche Agronomique - INRA
Université de Toulouse > Ecole Nationale Vétérinaire de Toulouse - ENVT
Laboratory name:
Statistics:download
Deposited By: Caroline Lacroux

Repository Staff Only: item control page