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U.S. Department of Health and Human Services

Animal & Veterinary

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by Linda Bren
FDA Veterinarian Newsletter 2002 Volume XVI, No III

This article appeared in the May/June 2002 issue of the FDA Consumer.

The prevention of bovine spongiform encephalopathy (BSE), commonly called mad cow disease, remains a top priority for the Food and Drug Administration and other government agencies.

BSE is a chronic, degenerative disorder affecting the central nervous system (brain and spinal cord) of cattle. A similar disorder in people, called variant Creutzfeldt-Jakob disease (vCJD), is believed to be caused by eating certain tissues from BSE-affected cattle. Both BSE and vCJD are fatal. Neither disease has ever been found in the United States.

A recent study by Harvard University gave high marks to government efforts to keep BSE out of the United States and to prevent its spread if it is ever found here.

The Harvard risk assessment study, released in November 2001, determined that the chances of BSE entering the United States and posing a risk to consumers and the agricultural industry are "extremely low." This three-year landmark study, commissioned by the U.S. Department of Agriculture (USDA), concluded that the joint efforts of the USDA and the FDA have been largely responsible for keeping BSE out of the country. Further, in the unlikely event that BSE would appear in U.S. cattle herds, the government's "multiple firewall" system would keep the disease from spreading so that it would eventually die out, according to the study. This firewall consists of a feed ban, import controls, and a surveillance program.

The Harvard study identified the feed ban as the linchpin of protection against the spread of BSE. Established in 1997 by the FDA's Center for Veterinary Medicine (CVM), the animal feed regulation prohibits feeding to cattle and other ruminants (such as sheep and goats) most mammalian protein, including a feed supplement known as meat-and-bone meal (MBM). Feeding cattle MBM that is contaminated with BSE is believed to be the most likely way for BSE to spread throughout a cattle herd.

Import controls are the critical safeguard against BSE being introduced into the United States. Since 1989, the USDA has banned the import of live ruminants and most ruminant products from the United Kingdom and other countries where BSE has been reported and from countries thought to be at high risk for BSE. The ban was expanded to include most of Europe in 1997 and Japan in 2001.

The third essential component of the firewall system of BSE prevention is the USDA's active surveillance program. The USDA has tested more than 21,000 cattle brains for BSE in the United States and Puerto Rico during the program's 11 years of operation and has found no evidence of BSE in American cattle.

"There are many places where one could intervene along the food chain to help prevent BSE," says Murray M. Lumpkin, M.D., the FDA's senior associate commissioner. "From the conception of the animal, through its raising and feeding, through the slaughtering and processing, to the marketplace, and to the preparation. Controlling all of these steps and the many people involved in them would be logistically impossible," says Lumpkin. But the Harvard study factored them all into their model to help determine which interventions have the greatest potential impact and what further actions the government could take to make the present very small risk of BSE in the United States even smaller. By using this simulation model and running dozens of hypothetical scenarios and many variations of each main scenario, the Harvard researchers concluded that compliance with the feed rule is one of the important keys to minimizing the risk of BSE.

Another study, released by the General Accounting Office (GAO) in February 2002, also noted the importance of feed rule compliance. The GAO study cited deficiencies in the FDA's oversight and enforcement of the feed rule.

"The FDA was well aware of these areas before the GAO report and was already making significant progress in addressing areas of concern so that we could strengthen further our public health protections," says Stephen Sundlof, D.V.M., Ph.D., director of the FDA's CVM.

The FDA's feed ban compliance and education efforts include a rigorous program to inspect establishments involved in the production of animal feed. With state feed inspectors, whom the FDA has under contract to help with these inspections, the FDA has completed initial inspections of all known animal renderers and commercial feed mills. Only about 4 percent of these entities were out of compliance with the feed rule.

"With an additional $13 million allocated to the FDA this fiscal year to oversee and enforce the feed regulation, the agency will hire 115 more people to expand BSE inspection efforts," says Sundlof. "This means we'll have an ongoing program to inspect and re-inspect every establishment that handles the prohibited material," he says. "We'll also increase our inspection coverage at the borders to help keep potentially BSE-tainted materials from entering our country."

The FDA has also implemented a new inspection tracking database, allowing the agency to record inspection results and track compliance more effectively.

Along with escalating its inspection program, the FDA plans to increase its sampling of domestic and imported feed to test for the presence of the prohibited protein. After holding a public meeting in Kansas City, Missouri, in October 2001, CVM is now reevaluating its feed rule to determine how to strengthen it to further reduce the risk of BSE. The Center will be issuing an advance notice of proposed rulemaking in the near future regarding possible changes in the feed ban rule.

"An important message from both the Harvard and the GAO studies is that we still need to be very vigilant, now and for a long time to come," says Lumpkin. "We must continue to work hard to make a good system even better. The FDA and the states will continue their aggressive inspection program and will continue to work closely with all components of the cattle and feed communities to help make a, thankfully, low public health risk even lower."

The latest information on BSE and the full report of the Harvard risk assessment study are available on the web.

Linda Bren is a Writer-Editor with the FDA Consumer.