When he entered his lab on Dec. 23, 2003, Allen Jenny, D.V.M., knew right away that something was wrong. He recalls the solemn expression on the face of a fellow scientist, who said, "I've got a slide to show you." Jenny, a U.S. Department of Agriculture (USDA) pathologist, peered through the microscope. What he saw was a bright red stain seeping into the gray matter of a slice of brain tissue--a telltale sign of bovine spongiform encephalopathy (BSE), otherwise known as mad cow disease.
"Are you sure it's a cow?" Jenny asked, a logical question in light of the fact that the National Veterinary Services Laboratory in Ames, Iowa, also tests sheep, deer, and other animals for mad cow-like diseases.
Yes, it was a cow, and this first diagnosis of BSE in the United States launched an emergency investigation that involved two countries--the United States and Canada--and regulatory changes by two U.S. government agencies to further bolster their effective safeguards to protect public health and livestock.
After U.S. authorities announced on the same day that a single dairy cow in Washington state was infected with the fatal brain-wasting disease, BSE, the Food and Drag Administration and the USDA took immediate action. While the USDA went to work to trace the origin of the cow and to initiate a recall of its meat, the FDA made sure that other portions of the cow, including the infectious brain and spinal cord, didn't get into animal feed or other FDA-regulated products. It is believed that BSE spreads when cows eat feed containing remnants of infected cattle. The FDA, which regulates animal feed, has banned the use of these remnants in feed for cattle and other ruminants, such as sheep and goats, since 1997. Canada implemented a similar ban at the same time.
USDA investigators and Canadian health officials found the herd the infected cow originally came from, identified her former herd mates, and then traced many of them to the herds they were later sent to.
"BSE does not spread from cow-to-cow contact," says Stephen F. Sundlof, D.V.M., Ph.D., director of the FDA's Center for Veterinary Medicine. "But we wanted to find these cows because they may have shared a common feed source when they were young," he says, and might also be infected.
An exhaustive search uncovered no other infected cows.
By the time the BSE investigation was completed in February 2004, the USDA had examined the identification tags and other devices on 75,000 cattle in three states--Washington, Oregon, and Idaho--and had humanely slaughtered 255 adult cattle and tested them for BSE.
Previously, in May 2003, Canadian authorities had reported finding the first native BSE cow in North America. Records indicated that this cow and the one found in Washington were more than six years old. "We now have very good evidence that both of these animals were born prior to the feed ban" in fire United States and Canada, says Ron DeHaven, chief veterinarian at the USDA.
Beginning as far back as 1989, the FDA and the USDA had set up a series of safeguards to protect against the spread of BSE. The two agencies have continually evaluated these safeguards and other possible measures to protect public health. After finding the BSE-infected cow in Washington, the agencies introduced some additional measures to further safeguard human and animal health.
The FDA and the USDA work in complementary roles to protect the food supply, and both have regulatory responsibilities. The FDA's responsibility in the human food area generally covers all domestic and imported food except meat, poultry, and frozen, dried, and liquid eggs, which are under the authority of the USDA. But the FDA does regulate certain foods that contain a small amount of meat, such as soups, gravies, and pizza with meat topping. In addition, the FDA regulates animal teed. …