[Spongiform encephalopathies in animals and humans].

Spongiform encephalopathies include several diseases of animals and humans: sheep and goat scrapie, bovine spongiform encephalopathy (BSE). Creutzfeldt-Jakob disease (CJD) in humans and its new variant (vCJD). Common characteristics of these diseases are long-term incubation, slow and progressive course, spongiform changes within nerve tissue, neuron loss and astrocytosis. Causative agent responsible for spongiform encephalopathy is prion (PrPsc) and it represents a posttranslationally modified host protein (PrPc) which normally exists and is produced in the cells. Development of certain diseases can be influenced by genetic factors, because of mutations in the PrP gene. Pathogenesis of these diseases is still not clear. In experimental peripheral infection the ineffective agent is first detected in the spleen and lymph nodes, and then it neurally spreads to the CNS. Bearing in mind that etiology, pathogenesis and mutual connection of spongiform encephalopathies have not been completely explained yet, caution and strict veterinary and sanitary measures are of great importance.