Tainted beef In the UK, the primary cause of<unk>  has been eating beef tainted with bovine spongiform encephalopathy. A 2012 study by the Health Protection Agency showed that around 1 in 2,000 people in the UK shows signs of abnormal prion accumulation. Jonathan Quick, instructor of medicine at the Department of Global Health and Social Medicine at Harvard Medical School, stated that bovine spongiform encephalopathy or BSE is the first man-made epidemic, or "Frankenstein"<unk> , because a human decision to feed meat and bone meal to previously herbivorous cattle (as a source of protein) caused what was previously an animal pathogen to enter into the human food chain, and from there to begin causing humans to contract<unk> . Blood products As of 2018, evidence suggests that while there may be prions in the blood of individuals with<unk>  this is not the case in individuals with sporadic CJD. In 2004, a report showed that<unk>  can be transmitted by blood transfusions. The finding alarmed healthcare officials because a large epidemic of the<unk>  could result in the near future. A blood test for<unk>  infection is possible but is not yet available for screening blood donations. Significant restrictions exist to protect the blood supply. The UK government banned anyone who had received a blood transfusion since January 1980 from donating blood. Since 1999 there has been a ban in the UK for using UK blood to manufacture fractional products such as albumin. Whilst these restrictions may go some way to preventing a self-sustaining epidemic of secondary infections, the number of infected blood donations is unknown and could be considerable. In June 2013 the government was warned that deaths, then at 176, could rise five-fold through blood transfusions. On 28 May 2002, the United States Food and Drug Administration instituted a policy that excludes from blood donation anyone having spent at least six months in certain European countries (or three months in the United Kingdom) from 1980 to 1996. Given the large number of U.S. military personnel and their dependents residing in Europe, it was expected that over 7% of donors would be deferred due to the policy. Later changes to this policy have relaxed the restriction to a cumulative total of five years or more of civilian travel in European countries (six months or more if military). The three-month restriction on travel to the UK, however, has not been changed. In New Zealand, the New Zealand Blood Service (NZBS) in 2000 introduced measures to preclude permanently donors having resided in the United Kingdom (including the Isle of Man and the Channel Islands) for a total of six months or more between January 1980 and December 1996. The measure resulted in ten percent of New Zealand's active blood donors at the time becoming ineligible to donate blood. In 2003, the NZBS further extended restrictions to permanently preclude donors having received a blood transfusion in the United Kingdom since January 1980, and in April 2006, restrictions were further extended to include the Republic of Ireland and France. Similar regulations are in place where anyone having spent more than six months for Germany or one year for France living in the UK between January 1980 and December 1996 is permanently banned from donating blood. In Canada, individuals are not eligible to donate blood or plasma if they have spent a cumulative total of three months or more in the UK or France from 1 January 1980 to December 31, 1996. They are also ineligible if they have spent a cumulative total of five years or more in Western Europe outside the UK or France since January 1, 1980 through 31 December 2007 or spent a cumulative total of six months or more in Saudi Arabia from January 1, 1980 through December 31, 1996 or if they have had a blood transfusion in the UK, France or Western Europe since 1980. In Poland, anyone having spent cumulatively six months or longer between 1 January 1980 and 31 December 1996 in the UK, Ireland, or France is permanently barred from donating. In the Czech Republic, anyone having spent more than six months in the UK or France between the years 1980 and 1996 or received transfusion in the UK after the year 1980 is not allowed to donate blood. In Finland, anyone having lived or stayed in the British Isles a total of over six months between 1 January 1980 and 31 December 1996 is permanently barred from donating. Sperm donation In the U.S., the FDA has banned import of any donor sperm, motivated by a risk of<unk> , inhibiting the once popular import of Scandinavian sperm. Despite this, the scientific consensus is that the risk is negligible, as there is no evidence<unk><unk><unk>  is sexually transmitted. Other causes Eating other types of brains such as those from squirrels is not recommended as one person contracted<unk> <unk><unk><unk>  from eating squirrel brains.
Variant Creutzfeldt–Jakob disease
Powassan encephalitis
Autoimmune encephalitis
Saint Louis encephalitis
Viliuisk encephalomyelitis
Japanese encephalitis
Anti-NMDA receptor encephalitis
Herpesviral encephalitis