[Transmissible spongiform encephalopathies in animals].

Transmissible spongiform encephalopathies in animals are known for centuries. In particular scrapie in sheep and goats occurs worldwide; it spreads as a natural disease and is genetically controlled. Chronic wasting disease (CWD) in the United States (Wyoming and Colorado) also spreads as natural disease among free ranging and captive elk and mule deer. In contrast, transmissible mink encephalopathy (TME) of mink in fur producing farms is caused by contaminated feed; the source of this food contamination is still controversial. The only occurrence of a TSE in an avian species was reported from a flock of ostriches in a German zoo. The origin of the outbreak of bovine spongiform encephalopathy (BSE) in Great Britain could be traced back to feeding concentrates containing animal proteins contaminated with the agent of sheep scrapie. BSE was introduced into other countries, e.g. Switzerland and France, through the import of contaminated feeds from Great Britain. In addition, sporadic cases of TSE occurred in 10 other species, in particular domestic cats and zoo animals, e.g. antelopes and large cats. The diagnosis is based on the neuropathological examination of the brain as well as the demonstration of the disease specific protease resistant prion protein (PrPres). The first measures against the disease aim at eliminating the risk factors. The most important is the prohibition of feeding animal protein concentrates to ruminants. Thanks to this measure the incidence of BSE diminished remarkably. To protect consumers of beef products, in countries with BSE the potentially infectious organs of all cattle are confiscated at slaughter. Yet, in Great Britain this measure was introduced only at a point of time when BSE had already spread all over the country. Therefore, there is a strong probability of an exposition of consumers of beef with the BSE agent, which might have caused the new variant of Creutzfeldt-Jakob disease (nvCJD).