Brain Trust Chapt 22: Origins 1957- Kuru Brains import 1963-70 Large scale inoculations Patuxent Multiple species => multiple prion strains deer cows minks squirrels humans Massive pervasive unseen underlying epidemic in wildlife????

Case against Kuru origin: Case for kuru origin: …progressive expansion in the cervid population ..temporal correlation with kuru experiments…1965 …recognition of various forms of prion disease in different species …squirrel outbreak and associated CJD deaths …1985 TME outbreak Case against Kuru origin: …mink cluster in 1961…evidence for TME in 1947 …mink cluster in 1961 originated from eating beef remains…disease already in beef …cervid infection originated from scrapie in sheep…introduced …expansion in cervids …very susceptible group of species …increased prevalence of disease due to more efficient farming practices …epidemic of BSE in UK and vCJD due to dramatic increase of prion-infected beef due to feeding of rendered meat. Despite low probability of infection, greater exposure to infected beef resulted in more vCJD

Is there a species barrier? …despite the amount of beef eaten, CJD cases are very rare…even in the disastrous situation in the UK, the fraction of the population dying of CJD is small …however, based on testing 32000 appendix samples, 1 in 2000 people in the UK are infected with abnormal prion protein …total UK deaths from CJD 1990-2014 is 1905 …total UK deaths from vCJD 1990-2014 is 177 (none in 2012, 1 in 2013, none in 2014 as of yesterday)

Steady state level