Biological safety of food and medicinal raw materials of animal origin: Modern data.

Prion infections of humans and animals are absolutely fatal. The cellular prion protein retains its antigenicity during the transition to the prion isoform; therefore, animals affected by prions do not respond to them with defensive reactions in the form of inflammation and the production of antibodies, which makes it difficult to diagnose the disease in vivo. In affected animals, prions accumulate in the nervous, lymphoreticular and muscle tissues and are released into the environment, in which they remain for many years. The resistance of prions to physical and chemical factors does not allow them to be inactivated in food by heat or radiation. Zoonoticity has been proven only for the causative agent of bovine spongiform encephalopathy, to which sheep, goats and pigs are susceptible. Sheep scrapie and chronic wasting deer disease occur widely in natural conditions in the form of enzootics and are similar in many characteristics. The zoonotic nature of their pathogens has not been proven. [ABSTRACT FROM AUTHOR]