Experts Predict U.S. Mad Cow Disease Will Spread
WASHINGTON, DC, February 6, 2004 (ENS) - Mad cow disease must now be considered "indigenous to North America," and the United States can no longer consider its first mad cow "an imported case," says an international scientific panel advising the U.S. Department of Agriculture (USDA).
At a USDA public hearing in Riverdale, Maryland on Wednesday, the five member panel said that while the dairy cow found to be infected with bovine spongiform encephalopathy (BSE) in Washington state last December was imported from Canada, it probably was not the only one.
"It is probable that other infected animals have been imported from Canada and possibly also from Europe," the panel warned. "These animals have not been detected and therefore infective material has likely been rendered, fed to cattle, and amplified within the cattle population, so that cattle in the U.S. have also been indigenously infected."
Mad cow disease, and similar diseases in elk, deer and humans, are spread by prions - abnormally shaped proteins that originate as normal components of central nervous system tissues.
Mad cow disease is not contagious, the panel stressed. It spreads when an animal consumes feed, such as meat and bone meal, that contains nervous system tissue from an infected animal.
The panel, which includes members from Switzerland, Britain, New Zealand, and the United States, is the same team that advised the Canadian government after its first case of BSE was found in Alberta in May 2003. Panel members predicted at the time that more cases of BSE would surface in Canada too, but to date no more have been found.
Chaired by Professor Ulrich Kihm of Switzerland, the group was appointed by Agriculture Secretary Ann Veneman to provide an expert opinion after the discovery of BSE in a downed cow from a Mabton, Washington herd was made public December 23. Laboratory confirmation of the disease several days later halted U.S. beef exports to some 40 countries worth about $3.8 billion annually.
The first U.S. mad cow had already been sent to slaughter and "the majority" of its brain, spinal cord and other tissues considered risk materials was rendered and did not enter the human food chain, the panel said.
This, in conjunction with the fact that beef meat is considered safe, "calls into question" the justification for the USDA's recall of some 20 tons of beef sold for human consumption, the panel said, while acknowledging that the recall was in accordance with World Health Organization standards.
The USDA's tracing of the rendered meat and bone meal that may have been contaminated with risk materials from the diseased cow was "effective and appropriate," but the scientists advised extra precautions to assure that this contaminated material is destroyed and does not enter commerce or trade.
The current U.S. Department of Agriculture (USDA) effort to identify the whereabouts of all animals from the U.S. mad cow's original herd in Canada is too "resource intensive" and "should cease," the panel said, because "it may not be possible to confirm the death or location of each and every animal." About half the mad cow's herd mates have been identified.
Instead, the agency should focus resources on the planning, implementation and enforcement of an extended, targeted, surveillance program to protect animals and humans from BSE.
Unless aggressive surveillance proves the BSE risk in the United States to be minimal according to international standards, the sceintists recommend that brain and spinal cord of all cattle over 12 months of age should be excluded from both the human food and animal feed chains. Presently, this risk material is banned from cattle over 30 months of age.
The intestines of cattle of all ages should also be excluded, the panel said.
In the meantime, until the level of BSE risk has been established, the panel said it "concedes" that exclusion of central nervous system, skull, and vertebral column from cattle over 30 months, and intestines from cattle of all ages, for use in human food is "a reasonable temporary compromise."
Tests in Britain, where BSE spread extensively through cattle in the 1980s and 1990s, showed cows could be infected when they ate feed that had been contaminated accidentally when manufactured in premises that legitimately used mammalian meat and bone meal in feed for pigs and poultry, the panel warned.
"Data from ongoing studies at the UK Veterinary Laboratories Agency show that cattle could be orally infected with as little as 10 milligrams (.0003 of an ounce) of infectious brain tissue," the panel reported.
The scientists acknowledged that prevention of cross-contamination at this level is "virtually impossible to deliver" where mammalian meat and bone meal intended for pig or poultry feed or pet food is present in feed plants that produce ruminant feed.
While supporting the need for "rigorous audit of compliance with feed controls," the panel said testing of feed and feed ingredients is unlikely to detect contamination of this low level because of the limitations of sampling techniques and test sensitivity.
Still, the panel warned, "Cross-contamination must be prevented throughout the feed chain, from reception and transportation of feed ingredients, during the manufacturing process, through transportation and storage of finished feed, and on farm where mixing, blending and feeding will occur."
Fishmeal can still safely be used for cattle feed, the panel said, provided that "the possibility for cross-contamination and deliberate adulteration are excluded" through compliance audits with testing.
On January 26, the Food and Drug Administration (FDA) banned the feeding of blood and blood products to cattle, saying recent scientific evidence suggests that blood can carry some infectivity for BSE. The agency also banned downer animals and those that died on farms before reaching the slaughter houses for use in human food, dietary supplements and cosmetics.
The FDA also banned the use of poultry litter as cattle feed. Poultry litter is bedding, spilled feed, feathers, and fecal matter collected from poultry houses and used in cattle feed in some areas of the country where cattle and large poultry raising operations are located near each other. Poultry feed may legally contain protein that is banned in cattle feed, such as bovine meat and bone meal.
The FDA ruled that cattle may no longer be fed "plate waste," uneaten meat and other meat scraps that are currently collected from some large restaurant operations and rendered into meat and bone meal for animal feed.
In addition, animal feed equipment, facilities or production lines may no longer process or handle both prohibited and non-prohibited materials and make feed for cattle as well as chickens or pigs, a practice which could lead to cross-contamination, the FDA said.
To comply with these rules and with the expert panel's recommentations, the meat industry will have to separate and dispose of massive amounts of specified risk materials as well as meat and bone meal.
The panel recognized that there is no established infrastructure for these activities and "accepted that a staged approach may be necessary for implementation."
Exclusion and destruction of such a high volume of raw material is a massive burden on all countries currently affected by BSE, the scientists said.
Because cattle are susceptible to BSE at such low doses, and because there is no commercial processing system that exists to guarantee destruction of infected materials, the future use of these risk materials in feed "may be impossible."
The panel recommended using these animal tissues "as a fuel source," but not in the manufacture of feed and fertilizers.
The panel said that while the USDA has recognized the importance of a national animal identification system, it should now be put in place. The USDA has been working on a traceability system for the past 18 months, but it has not yet been implemented.
They must be tested for surveillance purposes and to prevent potentially infective tissues from entering the food and feed chains. But since they will be excluded from supervised slaughter at inspected slaughterhouses, downer animals may no longer be available for the BSE surveillance program at these locations.
Therefore, said the panel, it is "imperative" that the USDA take additional steps, and spend additional funds, to allow for collection of samples from downer animals and proper disposal of their carcasses.
The panel recommends a system of financial incentives to encourage farmers to identify downer animals, and a strengthening of inspections after slaughter to identify questionable animals. Even animals that have passed inspections might have to be randomly sampled for BSE, the panel suggested.
Veterinary authorities were advised to educate farmers in "their role as producers of safe food," in order to achieve maximum surveillance of potentially infected downer animals.
To stem the spread of BSE, "Extensive national coordination and cooperation is imperative, and should be extended to include the continent of North America," the panel said.
The panel suggested that a BSE task force be established including both governmental and nongovernmental stakeholders, under the leadership of the USDA in order to assure that policies are developed and implemented in a consistent, scientifically valid manner.
Policy actions being considered by the United States must reduce public health risk for consumer protection, the panel said, and must limit recycling and amplification of the agent that causes BSE, establish the level of effectiveness of measures through surveillance, prevent any inadvertent introduction of BSE from abroad in the future, and contribute to the prevention of the spread of the epidemic worldwide.
Federal, state and local governments alone cannot achieve these goals, said the panel, and producers, consumers, private industry, and veterinary professionals should be involved.
But Caroline Smith DeWaal, Food Safety Director with the Center for Science in the Public Interest, called the panel's analysis "refreshingly candid," and said it shows that the USDA has "not done enough to protect both the animal and human food supplies."
"USDA should immediately implement the panel's recommendations, particularly by banning spinal cord and backbones from cattle 12 months and older from the human food chain," said DeWaal. "In addition, the FDA should ban all mammalian and poultry protein from cattle feed. That's really the only way American consumers and our trading partners around the world will have full confidence in the safety of American beef."
"All downer cattle on ranches must be tested, to ensure that ranchers don't try to hide evidence of the disease," she said.
Secretary Veneman said Tuesday that the Bush administration's budget request for fiscal year 2005 proposes $60 million to manage mad cow disease. If the request is approved by Congress, the USDA Agricultural Research Service would get $5 million to conduct advanced research and development of BSE testing technologies.
The USDA Animal and Plant Health Inspection Service would receive $17 million to continue collecting 40,000 samples to test for BSE, but testing of a larger number of samples would not be funded.
The USDA Food Safety and Inspection Service would receive $4 million to conduct monitoring and surveillance of compliance with the regulations for specified risk materials and advanced meat recovery.
And $1 million would go to the USDA Grain Inspection, Packers, and Stockyards Administration to enable rapid response teams to deal with "BSE related complaints in the cattle market regarding contracts or lack of prompt payment," Veneman said.
If the budget request is approved, the USDA would spend $33 million to accelerate the development of a National Animal Identification system.
DeWaal says all cattle should wear ID tags, but the beef industry and not U.S. taxpayers should bear the expense. "It's not surprising that the administration would try to subsidize the beef industry in this way, given that USDA is generously populated with former meat industry officials," said DeWaal. "But the expert panel's report clearly shows that the Bush administration needs to stop compromising with the industry, and instead act more aggressively to protect the public's health."