This is hard to fathom, given that the USDA can run only a few hundred of its immunohistochemistry (IHC) tests per day at its lab in Ames, Iowa. Rapid tests would increase that through-put. Widely used in Europe, they deliver results in hours instead of weeks, saving time, lab costs, and the expense of storing carcasses. And some tests are actually more sensitive than IHC tests, which are the USDA's "gold standard."
The agency should heed the experts because, at present, there is no way to gauge infection in U.S. herds. NAFTA effectively blurred the boundaries between the American and Canadian livestock and feed markets. Although the American mad cow was likely infected in Canada, where she spent her early years, tainted feed may also have circulated south of the border. Given her age at death -- 6 1/2 years -- and the average 4-to-5-year incubation period of the disease, she could have picked up a lethal dose almost any time in her first years. If she had been slaughtered just a month earlier, she would have passed untested into the food chain.
The USDA won't explain its hesitation on rapid testing. Perhaps it is frightened by what it might find. But precious time is being wasted. With each passing month, more of the older cattle -- the ones most likely to have eaten contaminated feed -- will be slaughtered. If we don't take a quick animal snapshot, we won't learn the extent of the problem until the next animals up the cow food chain -- humans -- get sick. By Janet Ginsburg in Chicago