THE EMERGENCE OF BOVINE SPONGIFORM ENCEPHALOPATHY AND RELATED DISEASES

Since 1986, approximately 170,000 cases of bovine spongiform encephalo pathy (BSE) have occurred among approximately one million animals infe cted by contaminated feed in the United Kingdom. A ruminant feed ban i n 1988 resulted in the rapid decline of the epidemic. Transmissible sp ongiform encephalopathies due to agents indistinguishable from BSE hav e appeared in small numbers of exotic zoo animals; a small outbreak am ong domestic cats is declining. Creutzfeldt-Jakob disease (CJD) has be en intensively monitored since 1990 because of the risk BSE could pose to public health. In 1995, two adolescents in the United Kingdom died of CJD, and through the early part of 1996, other relatively young pe ople had cases of what became known as new variant CJD, whose transmis sible agent (indistinguishable from that of BSE) is responsible for 26 cases in the United Kingdom and one in France. Areas of concern inclu de how many cases will appear in the future and whether or not use of human blood and blood products may cause a second cycle of human infec tions.