Mad Cow Disease: Two Forms of CJD

by Food and Drug Administration (FDA)

(Page 2 of 2)

Another human TSE, Creutzfeldt-Jakob disease, in its classic form, occurs worldwide at a rate of approximately one case per 1 million people per year. Classic CJD, unlike its new variant, nvCJD, is not known to be caused by consuming food made from cows infected with BSE.

"CJD and nvCJD are best thought of as two different diseases," says CDC's Schonberger. "CJD was around long before the emergence of BSE in cattle."

Victims of classic CJD and nvCJD may share some symptoms, but the patterns of the brain lesions are distinct. To date, nvCJD has caused disease in younger patients, and the mean duration of illness is more prolonged. (The average age for death of nvCJD has been 27.5 versus 68 for CJD, and the average time to death after the onset of clinical symptoms is 13 months for nvCJD versus less than six months for CJD.)

As of Feb. 2, 2001, a total of 94 cases of nvCJD have been confirmed or suspected in the UK, according to the UK Department of Health. Three cases in France and one in Ireland were reported by the European Commission's Health and Consumer Protection Directorate.

The U.S. Response

The focus for American animal and human health officials has been prevention. "Using the best science known at this time, the United States has an aggressive, multi-faceted program in place to try to prevent the establishment and spread of BSE," says Stephen Sundlof, DVM, PhD, director of FDA's Center for Veterinary Medicine. FDA's restrictions on certain cattle feed ingredients and its import alerts on cattle products are critical parts of this program. In addition, USDA has prohibited certain animals and animal products from entering the country.

Since 1989, USDA's Animal and Plant Health Inspection Service (APHIS) has banned the import of live ruminants (cattle, sheep, and goats) and most ruminant products from countries where BSE has been reported. In addition, in 1990, APHIS began a program of active surveillance of certain American cows for evidence of BSE. While FDA inspects feed production facilities, the USDA surveillance program condemns and tests any cows displaying signs of neurological problems at slaughter. As of October 2000, approximately 12,000 cattle brains from nearly every state and Puerto Rico had been examined, with no evidence of BSE found. More than 60 diagnostic laboratories continue to examine hundreds of cattle brains each year.

In August 1997, FDA established a regulation that prohibits the use of most mammalian protein in the manufacture of animal feeds for ruminants. With the strong support of renderers, cattle owners, feed manufacturers, and feed lot owners, FDA launched a compliance and education program, including a rigorous inspection program. The goal of these efforts is to achieve as close to 100 percent compliance with this new regulation as possible. FDA and state regulators have conducted nearly 10,000 inspections of renderers, feed mills, ruminant feeders, dairy farms, protein blenders, feed haulers, and distributors since January 1998. More than three-quarters of these establishments were found to be in compliance. And most of the establishments that initially had problems were found in compliance upon re-inspection.

Education is also an extremely important part of the compliance program. "We've put a lot of effort into getting the word out about the regulation," says Sundlof. FDA has sponsored workshops for state veterinarians and feed control officials from all 50 states, Puerto Rico, the U.S. Virgin Islands, and Canada. In addition, FDA has held briefing sessions with trade associations and consumer groups, and has developed additional guidances for complying with the regulation.

FDA is continuing its compliance efforts by conducting additional inspections and re-inspecting non-compliant facilities. Based on an evaluation of the inspections conducted from 1998 through 2000, FDA will revise its compliance strategy to try to assure its goal of 100 percent adherence to the feeding regulations.

FDA and USDA recently took emergency action to prevent potentially cross-contaminated products from entering the United States. On December 7, 2000, APHIS banned all imports of rendered animal proteins, regardless of species, from the more than 30 countries that either are known to have BSE in their cattle or otherwise present undue risk for introducing BSE into the United States. FDA has also announced an import alert, allowing its inspectors to detain shipments from these countries of animal feed (including pet food), animal feed ingredients, and certain other products of animal origin intended for animal use.

FDA and USDA will continue to aggressively enforce their regulations and to work closely with those in the cattle and feed industries to minimize the risk of BSE introduction or spread in U.S. cattle herds. FDA will develop new guidances and regulations as the scientific knowledge about BSE expands. Working together with many counterpart agencies in the United States and around the world and with various industry and consumer groups, FDA will continue to do its best to protect the health of Americans and of our American cattle herds.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.