Characterization of goat prions demonstrates geographical variation of scrapie strains in Europe and reveals the composite nature of prion strains

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Bovine Spongiform Encephalopathy (BSE) is the only animal prion which has been recognized as a zoonotic agent so far. The identification of BSE in two goats raised the need to reliably identify BSE in small ruminants. However, our understanding of scrapie strain diversity in small ruminants remains ill-defined, thus limiting the accuracy of BSE surveillance and spreading fear that BSE might lurk unrecognized in goats. We investigated prion strain diversity in a large panel of European goats by a novel experimental approach that, instead of assessing the neuropathological profile after serial transmissions in a single animal model, was based on the direct interaction of prion isolates with several recipient rodent models expressing small ruminants or heterologous prion proteins. The findings show that the biological properties of scrapie isolates display different patterns of geographical distribution in Europe and suggest that goat BSE could be reliably discriminated from a wide range of biologically and geographically diverse goat prion isolates. Finally, most field prion isolates showed composite strain features, with discrete strain components or sub-strains being present in different proportions in individual goats or tissues. This has important implications for understanding the nature and evolution of scrapie strains and their transmissibility to other species, including humans.

This work was funded by the European Union (FOOD-CT-2006-36353 to AB, JPML, OA, JMT, CA, MHG, PLA, UA, TS; and ERA-NET EMIDA GOAT-TSE-FREE to JPML, LVK, PLA, OA, JCE, CA, CF); the Dutch Ministry of Agriculture (project WOT-01-002-001.01 to JPML); the Spanish Ministerio de ciencia innovación y universidades (AGL2016-78054-R [AEI/FEDER, UE] and AGL2012-37988-C04-04 to JMT); the Italian Ministry of Health (RF-2009-1474624 to RN). AMM was supported by a fellowship from the INIA (FPI-SGIT-2015-02). PAC was supported by a fellowship from the Spanish Ministerio de Economía y Competitividad (BES-2010-040922). Te funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Peer reviewed