Released: May 21, 2003

K-State Scientists, Veterinarians Explain Mad Cow Disease

MANHATTAN, Kan. – News from Canada this week that bovine spongiform encephalopathy (BSE or mad cow disease) was found in an eight-year-old cow sent U.S. livestock futures markets tumbling, but it does not mean there’s an increased threat to the U.S. beef supply, Kansas State University veterinarians and animal scientists said.

The news prompted the U.S. Department of Agriculture to close U.S. borders to Canadian cattle and beef.

Also in response to the news, a task force of veterinarians, animal scientists and other experts representing the K-State Colleges of Agriculture and Veterinary Medicine was convened by Ralph Richardson, dean of the K-State College of Veterinary Medicine. Here’s what they had to say:

What is BSE?

K-State Task Force: BSE, also called mad cow disease, is a slowly progressing fatal disease that affects the central nervous system of cattle, said Larry Hollis, veterinarian and beef specialist with K-State Research and Extension. First diagnosed in Great Britain in 1986, it belongs to a family of diseases known as transmissible spongiform encephalopathies (TSEs). A number of other diseases of animals including scrapie (in sheep), chronic wasting disease (in deer and elk), and transmissible mink encephalopathy, as well as the human diseases, Creutzfeld-Jacob disease, kuru, Gerstmann-Straussler-Scheinker syndrome and Fatal Familial Insomnia are other examples of TSEs.

TSEs are thought to be caused by prions, a host-coded protein. If present, the agent is in the central nervous system and not in muscle meat.

Is it still safe to eat beef?

K-State Task Force: The disease has never been found in the United States. We have the safest beef supply in the world. Since BSE was first recognized in the United Kingdom, the United States has taken aggressive steps to protect consumers and prevent the disease from entering the country or occurring. We also have developed an extensive surveillance program to test for the disease. Driving a car or traveling in an airplane is a far greater risk.

What were the circumstances surrounding the case in Canada?

K-State Task Force: The cow, which was from a herd in the province of Alberta, did not enter the food chain, but instead was sent to a rendering plant after it was slaughtered on Jan. 31. The Canadian surveillance system is similar to that of the U.S., and this finding shows that the system works. The herd from which it came will be depopulated once samples are taken.

Has mad cow disease ever been found in North America?

K-State Task Force: No cattle have ever been diagnosed with BSE in the United States. This was the first case of BSE in Canada since a cow that had been imported from Britain was diagnosed with it in 1993.

What has our government done to keep mad cow disease out of this country?

K-State Task Force: The U.S. Department of Agriculture and the Food and Drug Administration have been proactive on this for a number of years. It’s been on their radar screen for a long time. Steps have been taken all the way from the producer to the beef processor including:

1) increased testing of cattle slaughtered over the past several years. In 2002, almost 20,000 cattle were tested, up from about 12,000 in 2001. We suspect that number will increase this year. To a large extent, the testing is targeted at ‘high-risk’ animals – those that are unable to walk at the time of slaughter, that died on the farm or showed signs of neurological distress;

2) In 1989, the USDA banned the import of live ruminants, such as cattle, sheep, goats and most ruminant products from countries that have or are considered to be at risk for having BSE;

3) In 1997, the FDA prohibited the use of most mammalian protein in the manufacture of animal feed intended for cows and other ruminants to stop the way the disease is thought to be spread; and,

4) Beef processors send tissue from the central nervous system to renderers for use in non-food products. The tissue does not go into the food chain.

Can people catch mad cow disease?

K-State Task Force: The disease is not transmissible through contact, either from animal to animal or animal to people. However, there is a disease called new variant Creutzfeldt-Jakob Disease (vCJD), which is a slow degenerative disease that affects the central nervous system in people. It has not been scientifically proven that eating tissue from BSE-infected animals causes vCJD, but according to the USDA, research supports a strong linkage between BSE and vCJD.

Hasn’t there been a problem with BSE in other parts of the world?

K-State Task Force: Since 1986, approximately 187,000 cases of BSE have occurred among nearly 34,000 herds, mostly in the United Kingdom. The epidemic peaked in 1993, with nearly 1,000 new cases reported weekly. About two-thirds were in dairy herds, while one in six beef herds had reported cases. The incidence of BSE in the UK has dropped dramatically, though, since prevention steps were introduced in the UK.

The disease has been confirmed in numerous other countries including Japan, Israel, Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Ireland, Italy, the Netherlands, Portugal, Spain and Switzerland.

Do they know how the UK outbreak happened?

K-State Task Force: The cases were believed to have resulted from feeding of scrapie-containing sheep meat-and-bone meal to cattle. Accordingly, there is general agreement that the outbreak was increased by feeding bovine meat-and-bone meal to cattle. That’s why the (U.S.) FDA banned the use of mammalian protein in the manufacture of feed intended for cows and other ruminants several years ago.

What are the clinical signs of BSE in cattle? Is there a test for it?

K-State Task Force: Affected animals may display changes in temperament, lack of coordination or difficulty in rising. It’s almost always been found in older animals, but that does not mean it can’t be in younger animals.

There is no reliable test to detect the disease in live animals. Scientists typically examine the suspected animal’s brain tissue to confirm a BSE diagnosis.

How long does it take an animal to become sick from BSE?

K-State Task Force: The incubation period ranges from two to eight years. After the onset of symptoms, the animal’s condition deteriorates until it dies or is destroyed – usually within two weeks to six months. Most cases in Great Britain occurred in dairy cows ranging from three to six years old.

I’ve heard about chronic wasting disease (CWD) in deer and elk in the United States. Can it be passed to cattle or people?

K-State Task Force: Chronic wasting disease is an infectious, neurological disease of deer and elk that has been found in Kansas and numerous other states. It, like BSE and vCJD, is in the group of diseases called transmissible spongiform encephalopathies (TSEs). As far as is currently known, neither people nor common farm livestock, including cattle, sheep and pigs, are susceptible to CWD. CWD has been known since the late 1960s and no cases have been discovered linking any disease in humans or livestock to CWD. Even where wild deer and elk share common pastures with domestic livestock, there has been no evidence of natural transmission to livestock.

Is mad cow disease the same as foot-and-mouth disease (FMD)? If not, what’s the difference?

K-State Task Force: No. Foot-and-mouth disease is a highly contagious viral disease found in cloven-hoofed animals including ruminants and swine. While FMD typically affects a large percentage of animals in a group and causes great production losses, it does not infect humans and is not a human health risk. In contrast, BSE occurs only sporadically in a herd and is not known to be contagious from animal to animal or animal to human.

Where can I learn more about BSE or mad cow disease?

K-State Task Force: There are several Web sites that have information. One is the USDA’s at

http://www.usda.gov/. K-State Research and Extension publication MF2434.asp Bovine Spongiform Encephalopathy (BSE) can be obtained through K-State Research and Extension offices. The National Cattlemen’s Beef Association (http://www.beef.org) also has information as does the Food and Drug Administration Web site at http://www.fda.gov/ .

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Sidebar:

USDA Outlines Steps Taken

To Prevent BSE in U.S.

MANHATTAN, Kan. – The U.S. Department of Agriculture has taken steps since 1988 to keep Bovine Spongiform Encephalopathy (BSE), also known as mad cow disease, out of U.S. cattle herds. The following is a time line of the steps taken over the years:

1988 - USDA establishes a BSE Working Group to review available science and recommend appropriate regulatory controls.

1989 - USDA bans the importation of live ruminants (cattle, sheep, goats, etc.) and most ruminant products from the United Kingdom and other countries where BSE was diagnosed.

1990 - USDA begins educational outreach of veterinarians, cattle producers, laboratory diagnosticians, etc. about the clinical signs and diagnosis of BSE. USDA initiates surveillance program to examine brains of U.S. cattle.

1997 - USDA prohibits importation of live ruminants and most ruminant products from all of Europe. USDA supports FDA regulations to prohibit the feeding of most mammalian proteins to ruminants.

2000 - USDA prohibits all imports of rendered animal protein products, regardless of species, from Europe.

2001 - USDA prohibits edible ruminant products from a non-BSE country from being transported to a BSE-infected country or BSE at-risk country for storage or processing unless the material was received, stored or processed in a facility that did not receive, store or process ruminant material from a BSE-affected or BSE at-risk country. The intent was to further assure that edible ruminant products from non-BSE countries are not cross-contaminated with ruminant products from a BSE country.

2001 - The USDA released a landmark study by Harvard University that showed the risk of BSE occurring in the United States is extremely low. The report showed that early protection systems put into place by the USDA and Department of Health and Human Services have been largely responsible for keeping BSE out of the U.S. and would prevent it from spreading if it ever did enter the country.

May 20, 2003 - USDA places Canada under BSE restriction guidelines and bans any ruminants or ruminant products from Canada pending further investigation. USDA also announces plans to dispatch a technical team to Canada to assist in the investigation.

-- Information compiled by K-State Research and Extension from U.S. Department of Agriculture information.

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K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by:
Mary Lou Peter & Nancy Peterson, Communications Assistant
mlpeter@oznet.ksu.edu, nancyp@oznet.ksu.edu
K-State Research& Extension News