Letter to the USDA Regarding Increased Testing for Mad Cow


July 18, 2003
Secretary Ann M. Veneman
U.S. Department of Agriculture
14th and Independence Ave., SW
Washington, D.C. 20250
Dear Secretary Veneman,
We are writing about the actions that USDA should take in response to the discovery of a BSE case in Canada on May 20. We urge the USDA to dramatically increase current surveillance for bovine spongiform encephalopathy (BSE), also known as mad cow disease, in the US and to authorize the use of rapid tests. We further urge USDA to take whatever steps are necessary to ensure that no central nervous system (CNS) tissue is present in meat intended for human consumption. We urge you not to open the border to imports of ruminants and ruminant products from Canada until both Canada and the US have taken these steps, which will protect consumer health and the long-term viability of the beef industry.
Last year, the Animal Plant Health Inspection Service (APHIS) tested some 19,990 brains for BSE. We feel this number is far too small. There are five rapid tests, based on the use of antibodies to the prion protein, which have been approved for use in the European Union. The companies that market these tests are Enfer, Prionics (2 tests), Bio-Rad, and InPro. Of these companies, two—Bio-Rad and InPro, are American. These tests are far cheaper and give results far more quickly than the testing methodology presently used by APHIS. In addition, the most recently approved test—the one developed by InPro—is based on new technology (the conformation-dependent immunoassay, or CDI) developed in the lab or Dr. Stanley Prusiner of UCSF, who received the Nobel Prize in 1997 for the prion theory. The diagnostic test based on the CDI appear to be more sensitive and accurate than the other rapid test (see the enclosed paper from October, 2002 issue of Nature Biotechnology). We urge APHIS to investigate the accuracy and sensitivity of all five tests, and to approve one or more to be used in testing brains of cattle.
APHIS has argued that 19,990 tests is far more than the number of tests needed given the size of the U.S. herd. The APHIS website states that the Office of International Epizootics (OIE) states that, given the U.S. herd size, only 433 cow brains need to be tested. This number is indeed found in Article 3.8.4.2 of the OIE’s International Animal Health Code
(http://www.oie.int/eng/normes/mcode/A_00155.htm). However it refers to the minimum number of animals, out of all those showing suspicious signs of BSE such as “excitability, persistent kicking when milked, changes in herd hierarchical status, hesitation at doors, gates and barriers” that should be tested, given a total herd size like that in the US. The very next clause of the Animal Health Code recommends that another groups of cattle be tested as well. Article 3.8.4.3 states, “Cattle that have died or have been killed for reasons other than routine slaughter (including ‘fallen’ stock and emergency slaughter) should be examined.” These two categories, fallen stock and emergency slaughter, basically comprise what is called the nonambulatory or “downer” cattle population. The USDA estimates that there 195,000 downers cattle each year in the United States, while Dr. Stanley Prusiner estimates that there are about one million (see http://www.kqed.org/programs/programarchive.jsp?progID=RD19&ResultStart=1&ResultCount=10&type=radio). Dr. Prusiner bases his estimate on the fact that detailed statistic from the United Kingdom show that approximately 1% of the national herd are considered “downer cows.” Given that the U.S. herd size was 97 million in 2002, this would suggest that there were 970,000 downer cattle. Regardless of which estimate is correct, we urge the USDA to listen to OIE and, at a minimum, test all “downer” cattle using one of the rapid tests.
We are also concerned that the Canadian Food Inspection Agency (CFIA) report stated that there was a small possibility that the Canadian BSE cow was born in the U.S. and entered Canada in 1998 when some 25,000 pregnant cows were imported from the U.S. According to news media, the report states, “Canada cannot, to date, exclude the possibility that the index case itself derived through this huge, unique importation” (http://www.newsobserver.com/24hour/science/story/934164p-6517121c.html). Some 70% of these pregnant cows were Black Angus, the same breed as the BSE cow. We also note that the same new stories state that the international team of experts that assessed Canada’s investigation of the mad cow case came to no conclusion about the origin of the cow. What has the USDA done to investigate the possibility that this animal came from the U.S.? Has the genetic history of the BSE cow been determined so that it can be determined with 100% certainty where she was born? If there is any possibility that the cow came from the US, this would suggest that further testing needs to be done.
In addition, USDA cannot rely on the Food and Drug Administration’s (FDA’s) 1997 BSE feed rule being rigorously enforced. Because of serious lapses, increased surveillance is needed. The USDA-sponsored Harvard risk assessment of the risk of BSE in the U.S. noted that compliance with FDA’s 1997 BSE feed rule is the most important factor in preventing a BSE outbreak. Yet a pair of reports by GAO—one published in September 2000 and the other published in January 2002—have shown how lax FDA has been in ensuring compliance with the feed rule. The first report, published some three years after the BSE feed rule went into effect found fairly widespread non-compliance: “inspection results of the 2,481 firms that were identified as handling ‘prohibited’ materials . . . 699, or 28 percent, did not label their products with the required cautionary statements that the feed should not be fed to cattle or other ruminants. . . . In addition, of the 1,771 firms that manufacture both prohibited and non-prohibited material, 361, or 20 percent, did not have a system in place to prevent commingling and cross contamination, as required by the regulation” (pp. 11-12 in http://www.gao.gov/new.items/rc00255.pdf). The 2002 GAO report found that, “(C)oncerning the feed ban, FDA has not acted promptly to compel firms to keep prohibited proteins out of cattle feed and to label animal feed that cannot be fed to cattle. . . . Moreover, FDA’s data on inspections are severely flawed and, as a result, FDA does not know the full extent of industry compliance. FDA acknowledges that it has not yet identified and inspected all firms subject to the ban” (pg. 3 in http://www.gao.gov/new.items/d02183.pdf). The report concludes that “federal actions do not sufficiently ensure that all BSE-infected animals or products are kept out or that if BSE were found it would be detected promptly and not spread to other cattle through animal feed or enter the human food chain” italics added (pg. 3 in http://www.gao.gov/new.items/d02183.pdf). The failure of FDA to fully implement the 1997 BSE feed ban should spur USDA to exercise greater vigilance to ensure that if BSE occurred in the US that it would be found quickly. USDA should therefore dramatically expand the testing of cattle to ensure, at a minimum, that all downer cows (e.g. all emergency slaughter and all fallen stock) are tested for BSE using one of the rapid tests, preferably the one found to be the most accurate (e.g. with the lowest rate of false positives and false negatives).
We also believe that USDA should act to ensure that no CNS tissue is found in meat destined for human consumption. We note that the results of the Food Safety Inspection Service’s 2002 AMR survey found that “about 74 percent (25 of 34) of the establishments tested in the AMR Survey of 2002 had positive laboratory results for CNS tissue in their final beef AMR products”; the other 26 percent had negative laboratory results (see pg. 2 of http://www.fsis.usda.gov/OA/topics/AMRSurvey.pdf). The USDA should take appropriate action to ensure that there is zero CNS contamination of meat destined for human consumption.
Canadian surveillance efforts are also insufficient. Both the US and Canada, as of last year, tested approximately one in every 5,000 animals in the total herd, whereas Europe test approximately one in every four animals (it tests all animals over a certain age at slaughter).
We urge you to keep the ban in place on importation of Canadian beef until surveillance on both sides of the border is increased dramatically.
Sincerely yours,
Jean Halloran Michael Hansen, Ph.D.
Director Senior Research Associate