Experimental Challenge of Cattle with German Atypical Bovine Spongiform Encephalopathy (BSE) Isolates

Abstract

For almost two decades after the discovery of the first bovine spongiform encephalopathy (BSE) case, it was generally accepted that only one BSE strain existed globally. However, in 2004, two novel BSE forms (L-type and H-type) were separately identified in two different European Member States, forms that differed from the classical (C-type) form by their biochemical properties and by the pattern of PrP^Sc deposition as determined by immunohistochemistry (IHC). 60 atypical BSE cases have been identified worldwide as of November 2010, including one H- and one L-type BSE case each in Germany. However, it was not known whether the biological properties (pathogenesis and agent distribution, as well as transmissibility to other species) of these novel forms were the same as in classical BSE cases. Eleven calves were thus challenged intracranially, five with the German H-type and six with German L-type BSE cases. The experimental design and the clinical studies, followed by laboratory testing, are described in this manuscript.

Acknowledgments

The cattle challenge study was funded by the German Ministry of Food, Agriculture, and Consumer Protection (BMELV). Extensive analysis of the samples is being funded by Health Canada. Special thanks to Ben Schiller and Volker Netz, who contributed to this study by looking after the BSE-challenged cattle in a very professional and responsible way.