USDA ends BSE investigation; experts call for more safeguards

Tougher regulations, implementation of national identification program, and more international cooperation urged
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Courtesy of Dr. Wayne Weiland

The Department of Agriculture ended its investigation of the first U.S. case of bovine spongiform encephalopathy Feb. 9.

The conclusion of the investigation came less than a week after a panel of international BSE experts released a report urging the department to shift its focus from the investigation to boosting safeguards against the spread of the disease.

During the investigation, the United States searched for 80 cattle that were imported from the same Canadian dairy as the infected cow, according to Dr. Ron DeHaven, chief veterinary officer of the USDA. Including the infected cow, the USDA has positively identified 29 of the 81 animals. The 28 confirmed herd mates of the infected cow and 227 other cattle that may have come from the source herd in Canada were killed and tested for BSE; none was positive.

"We feel very confident that the remaining animals, the ones we were not able to positively identify, represent little risk," Dr. DeHaven said.

The international panel includes many of the same experts who evaluated Canada's response to the discovery of a case of BSE in an Alberta cow last spring. A subcommittee of the U.S. Secretary of Agriculture's Foreign Animal and Poultry Disease Advisory Committee, the panel presented its report to the committee on Feb. 4. The panel consisted of Drs. Ulrich Kihm and Dagmar Heim of Switzerland, Dr. William D. Hueston of the United States, Dr. D. Matthews of the United Kingdom, and Dr. Stuart MacDiarmid of New Zealand.

While the panel acknowledged that many of the measures the USDA has implemented are appropriate, it criticized the department's assertion that the first U.S. cow infected with BSE was an isolated case from Canada.

On the contrary, the panel's report concluded that, because the U.S. and Canadian cattle industries are highly integrated, the disease agent is now circulating in the United States, and BSE must be treated as an indigenous disease.

"The significance of this BSE case cannot be dismissed by considering it 'an imported case,'" according to the report.

Since the case of BSE was confirmed Dec. 25 in a nonambulatory dairy cow in Washington state, the USDA and the Food and Drug Administration instituted additional safeguards against the spread of BSE.

The international panel's report, however, suggests those measures do not go far enough. The report urges that the United States make its existing regulations even tougher by:

  • banning all BSE risk material from the feed chain
  • banning all mammalian and avian protein from cattle feed, not just ruminant protein
  • prohibiting the use of the entire intestine in human food, not just the small intestine
  • requiring meat processors to exclude skull, brain, vertebral column, spinal cord, and other potentially infective materials from cattle more than 12 months of age, instead of more than 30 months of age
  • instituting a very aggressive surveillance program testing all at-risk animals and some healthy animals for at least a year
  • discontinuing the use of mechanical meat recovery systems
  • supporting research on BSE and efforts to develop new diagnostic tests
  • launching an aggressive public and professional education campaign

Dr. DeHaven said the USDA and the FDA are analyzing those recommendations.

Dr. Hueston said implementing a ban on BSE risk materials in the feed supply is the most important recommendation. He said the second most important recommendation is instituting an aggressive surveillance campaign to test all high-risk cows for the next year—a necessary step to gauging how much infectivity is present.

In addition to emphasizing the need to institute tougher disease control measures, the panel encouraged the implementation of the national animal identification system. Agriculture Secretary Veneman announced Dec. 30 that the USDA is in the process of implementing the system.

The panel recognized that some measures the USDA took following the discovery of BSE were appropriate and effective. Among them were tracing meat and bonemeal from the infected cow, the intent of the USDA to use a science-based approach, and the implementation of a ban of high-risk materials, such as spinal cord and small intestine, from animals more than 30 months of age from the food supply, in accordance with the standards set by the Office International des Epizooties.

Dr. Hueston said that by banning high-risk materials from human food, "(the USDA has) taken the single most important step to protect public health."

The panel also recognized that some countries have not followed international regulations on the control of BSE and have instituted "irrational trade barriers." To prevent this in the future, the panel urged the United States to adopt international standards and encourage other countries to do so.

Some industry groups, including the National Cattlemen's Beef Association and the American Meat Institute, have criticized the report for not taking into account control measures already in place and overestimating the amount of infective agent present in North America.

Dr. Dawn Capucille, chair of the American Association of Bovine Practitioners' Food Quality, Safety, and Security Committee, said she concurred with some of the report's findings—including the importance of implementing a national animal identification program. She felt, however, the report overstated the level of disease amplification that may be taking place.

"BSE is not that easily transmitted, and we have a lot of firewalls in place," Dr. Capucille said.

Dr. Hueston said that the committee's threefold charge—to examine the science, international standards, and the lessons learned from the experiences of other countries—excluded looking at current safeguards in the United States.

After looking at the practical difficulties other countries experienced trying to prevent cross-contamination of cattle feed, the committee concluded that it is necessary to create a redundant system of safeguards to prevent cycling of BSE in the feed chain, Dr. Hueston explained.

Overall, Dr. Hueston applauded the openness of the United States.

"It was pretty gutsy of the United States to ask for an international review," he said. "In most other countries, it would have been secret. The fact that it has been done and it's being talked about is a compliment to the openness of the process."