The biggest documented prion disease outbreak was in Great Britain. Between 1988-1998, there were 173,952 cases of confirmed BSE, which spanned over 34,500 herds (Belay, 1999). Based on the confirmed number of BSE cases and the number of cows tested, estimated cases of BSE in the same time frame were around 2 million infected cows (Belay & Schonberger, 2005). The hypothesized method of transmission was from feeding scrapie infected sheep meat through the meat-and-bone meals to cows. This outbreak was incredibly important because approximately 750,000 infected cows were slaughtered between 1980-1996 and potentially consumed by residents of the U.K. (Belay & Schonberger, 2005). A large number of humans acquired vCJD through consuming of infected cow meat. As of November 1, 2004, 151 BSE cases had been reported in the U.K. (Belay & Schonberger, 2005). Upon this massive outbreak, a number of public health measures were put into place to prevent further BSE epidemics. These regulations included a ban on slaughtering cows over 30 months for human consumption (Belay & Schonberger, 2005). Most importantly, regulations were put into place that stated mammalian protein could no longer be fed to any farm animals. This was probably the most important safeguard that was implemented because it has potentially prevented outbreaks. BSE continues to be detected in animal populations at low rates even with the newer regulations. It is currently thought that this continued level of BSE is likely due to repeated exposure to contaminated materials of which only very small amounts are required to elicit an infection (Belay & Schonberger, 2005).