[Update on transmissible spongiform subacute encephalopathies (TSSE)].

This update concerns human and ruminant transmissible spongiform subacute encephalopathies (TSSE). The latest data on variant Creutzfeldt-Jakob disease confirm that new cases are less frequent than feared some years ago, but subclinical carriers could be a source of iatrogenic infection. The macaque is a good model of human oral transmission of bovine spongiform encephalopathy (BSE). The latest data on BSE in Europe confirm the effectiveness of precautionary measures taken in 1996 and 2000. Concerns in other ruminants include a chronic wasting disease of Cervidae in North America, the discovery of a BSE-like agent associated with natural scrapie in a French goat, maternal transmission of natural scrapie in sheep, with an exceptionally short incubation period (6.5 months), and doubts over the efficacy of genetic selection for combating ovine scrapie (atypical cases in " resistant " sheep, especially with the scrapie strain Nor 98 in Europe). These data demonstrate the value of active European surveillance of scrapie in small ruminants.