Takashi Onodera and Katsuaki Sugiura
from: Prions: Current Progress in Advanced Research (Edited by: Akikazu Sakudo and Takashi Onodera). Caister Academic Press, U.K. (2013)
Results in Netherlands show that classic scrapie control can be obtained at the national scale without a loss of genetic polymorphism from any of sheep breed. No classical scrapie strain thus far has escaped ARR-associated resistance. Ongoing studies show that atypical scrapie strain also was controlled by ARR-associated resistance. In line with this expectation, the breeding program proved successful in Dutch flock in 2010. When considering the rapid outbreak control as observed in Netherland study, the use of resistant rams seems sufficient and can be recommended as a control strategy in scrapie-affected countries. The origin of atypical BSE cases is currently unknown. As with classical BSE, exposure of these animals to feed contaminated with low titers of TSE agent cannot be excluded, although other origins for these TSE forms cannot be discarded. In particular, the unusually old ages of all H-BSE and L-BSE identified cases and their apparent low-prevalence in the population could suggest that these atypical BSE forms are arising spontaneously. PMCA needs to be highly standardized and robust in terms of a consistent and objectively quantifiable PrPres amplification if to be used for quantification of the proteinaceous seeding activity of prions. There is a direct quantitative correspondence between the seeding and infectious activities of 263K scrapie prions measured by RT-QuIC and bioassay. The methodological, conceptual and practical results described in the report of 263K scrapie prions should be validated for the most human TSE agents. Although scrapie has been known for decades, relatively little attention has been paid to it as a natural disease of sheep and goats mainly because the economical impact has been relatively small compared to other diseases in sheep. The occurrence of bovine spongiform encephalopathy (BSE) provide a new impetus to research into the transmissible spongiform encephalopathies (TSE). Not only was the economical impact of BSE much greater than that of scrapie, the link with variant Creutzfeldt-Jakob disease (vCJD) in humans also gave rise to serious concerns regarding food safety read more ...