Transmission of bovine spongiform encephalopathy and scrapie to mice

Abstract

Transmission from four cases of bovine spongiform encephalopathy (BSE) to mice resulted in neurological disease in 100% of recipient animals, after incubation periods of between 265 and 700 days post-injection. The results from the four cases were very similar to one another. There were major differences in the incubation period between the four inbred strains of mice tested, and even between strains of the same Sinc genotype, and the incubation periods of Sinc heterozygote mice were much longer than those for any of the inbred strains. Transmission from a case of natural scrapie differed in two important respects: there were no differences in the incubation period between mouse strains of the same Sinc genotype, and that of the heterozygotes was between those of the Sinc homozygotic parental strains. The distribution of vacuolar degeneration in the brains of mice infected with scrapie also differed from those infected with the BSE isolates. Transmission was also achieved from formol-fixed BSE brain. These results show that the same strain of agent caused disease in the BSE cases, and that the relationship of BSE to scrapie in sheep is unclear.

The epidemiology of BSE in cattle herds in Great Britain. I. Epidemiological processes, demography of cattle and approaches to control by culling

“…In experiments similar to those undertaken for scrapie, BSE was transmitted to mice from seven unrelated and geographically distant cattle hosts. The consistency of the pathology and incubation period observed for all seven BSE sources suggests that all seven were infected with the same strain of BSE (Fraser et al 1992;Bruce et al 1994;Bruce 1996).…”

“…meal (MBM) contaminated by a scrapie-like agent derived from sheep or cattle. The oral route of infection for transmissible spongiform encephalopathy (TSE) agents has been demonstrated experimentally (Barlow & Middleton 1990;Fraser et al 1992;Middleton & Barlow 1993;Wells et al 1994;MAFF 1996). Subsequent epidemiological investigations undertaken in 1988 and 1989 revealed that the consumption of MBM from infected cattle was the probable cause of the rapid development of the epidemic in the cattle population within Great Britain (GB) (Wilesmith et al 1988(Wilesmith et al , 1991.…”

Molecular Analysis of the Protease-Resistant Prion Protein in Scrapie and Bovine Spongiform Encephalopathy Transmitted to Ovine Transgenic and Wild-Type Mice

“…The existence of different TSE strains has been essentially defined by the different features of the disease, including differences in the incubation periods and in the distribution of brain lesions, following TSE transmission in mice of different genotypes (24). Nevertheless, this has been most extensively demonstrated in natural scrapie; in contrast, a unique and stable BSE strain has been recognized in cattle BSE (11,23). Scrapie strain diversity still remains a matter of controversy (51).…”

Prion distribution in hamster lung and brain following intraperitoneal inoculation.

“…One could argue that direct bioassay of BSE prions in cattle provides the best system for ascertaining titres in bovine tissues but the expense required to achieve the statistical power of an animal model makes this approach impractical. The alternative bioassay system, inoculation of BSE prions from bovine tissues into mice, may be as much as 1000-fold less sensitive than if the measurements were made in cattle (Fraser et al, 1992 ;Bruce et al, 1994 ;Wells et al, 1998). Scott et al (1997) recently described construction of transgenic mice that possess a bovine PrP transgene but lack the mouse PrP gene.…”