Meanwhile, Agriculture Secretary Ann M. Veneman said the department was seeking money for additional efforts. She said financing would be increased for the Animal and Plant Health Inspection Service, which works to prevent disease transmission and for border inspections to keep infected animals out of the country. Mad cow disease, formally known as bovine spongiform encephalopathy, or B.S.E., leaves brain tissue spongy and full of holes. Other animals are infected by similar transmissible spongiform encephalopathies, among them scrapie, in sheep, and chronic wasting disease, in deer and elk. The human form, Creutzfeldt-Jakob disease, was identified in 1926 and kills about 250 Americans a year.
Some people inherit a susceptibility to the incurable disease, but causes in most cases are unknown.
Until recently, scientists believed that the disease seen in one species could not infect members of other species. But in 1996 doctors in Britain identified young people who seemed to have Creutzfeldt-Jakob disease, which typically strikes the elderly. The disease has now claimed more than 100 lives, most of them in Britain. Dr. Marcus Doherr, a veterinarian epidemiologist at the University of Bern, in Switzerland, said the United States should test more slaughtered cattle for signs of B.S.E. Dr. Doherr helped develop the Swiss testing program, which many experts consider the most advanced. Dr. Thomas Pringle, who runs the Sperling Biomedical Foundation in Eugene, Ore., and is an authority on mad cow disease, points out that many downer cows go directly from the farm to the plant where they are turned into feed without being tested.