What is "Mad Cow Disease" (Bovine Spongiform
Encephalopathy/BSE)?
Mad
Cow Disease is the commonly used name for Bovine Spongiform
Encephalopathy (BSE), a slowly progressive, degenerative, fatal disease
affecting the central nervous system of adult cattle. Since 1990, the
U.S. Department of Agriculture (USDA) has conducted aggressive
surveillance of the highest risk cattle going to slaughter in the
United States, in which 10,000- 20,000 animals per year have been
tested. To date, the only cow that has been found to be affected with
BSE was the one diagnosed with BSE in December 2003.
What causes BSE?
The
exact cause of BSE is not known but it is generally accepted by the
scientific community that infectious forms of a type of protein,
prions, normally found in animals cause BSE. In cattle with BSE, these
abnormal prions initially occur in the small intestines and tonsils,
and are found in central nervous tissues, such as the brain and spinal
cord, and other tissues of infected animals experiencing later stages
of the disease.
Was a case of BSE identified in the U.S. in December 2003?
Yes,
the USDA surveillance program identified the first BSE case in the U.S.
in a dairy cow in Washington State. The cow was bought from a farm in
Canada.
Did meat and meat products from the BSE cow enter the food
supply?
As
soon as the BSE case was identified, both USDA and FDA activated their
BSE Emergency Response Plans and USDA immediately recalled the meat.
Meat that did enter the food supply was quickly traced and was removed
from the marketplace. Moreover, all the organs in which infectious
prions occur were removed at slaughter and did not enter the food
supply. Scientific research indicates that muscle meat is not a source
of infectious prions. As a result of the agencies' quick actions and
the removal of organs that contain infectious prions, there is no
significant risk from products of this animal.
FDA
and state inspectors located all other parts of the animal, and
rendering plants that processed this material from the BSE cow
voluntarily held the material. None of this material left the control
of the companies and entered commercial distribution.
Will there be additional cases?
Regulatory measures to prevent introduction of BSE into U.S.
cattle herds and contamination of U.S. foods and food products are
being reviewed and updated. Since 1989, the USDA has banned imports of
live ruminants, such as cattle, sheep and goats, and most products from
these animals from countries known to have BSE. This ban was extended
to all Europe in 1997. The FDA prohibited the use of ruminant protein
in the manufacture of animal feed intended for cows and other ruminants
in 1997 and extended the prohibition in 2001 to forbid use of all
mammalian protein in ruminant feed. See the FDA/CVM website at www.fda.gov/cvm for further information on the "ruminant
feed ban".
Under
an Import Alert, FDA also prevents U.S. entry of cosmetic and dietary
supplement ingredients containing high risk bovine materials from
animals originating in BSE countries.
In
1998, the USDA commissioned the Harvard Center for Risk Analysis to
conduct an analysis and evaluation of the U.S. regulatory measures to
prevent the spread of BSE in the U.S. and to reduce the potential
exposure of U.S. consumers to BSE. The Harvard study concluded that if
introduced, due to the preventive measures currently in place in the
U.S., BSE is extremely unlikely to become established in the United
States. Should BSE enter the United States, the Harvard study concluded
that only a small amount of potentially infective tissues would likely
reach the human food supply.
Furthermore, on Jan. 8, 2004, the USDA's Food Safety and
Inspection Service issued four new rules to enhance safeguards against
BSE. Details on these rules may be found at the USDA website, www.usda.gov.
Does BSE affect people?
There
is a disease similar to BSE called Creutzfeldt-Jacob Disease (CJD) that
is found in people. A variant form of CJD (vCJD) is believed to be
caused by eating contaminated beef products from BSE-affected cattle.
To date, there have been 155 confirmed and probable cases of vCJD
worldwide among the hundreds of thousands of people that may have
consumed BSE-contaminated beef products. The one reported case of vCJD
in the United States is in a young woman who contracted the disease
while residing in the UK and developed symptoms after moving to the U.S.
What additional measures are being taken to ensure food
safety in the U.S. from BSE?
Since
1989, the FDA and other federal agencies have had ongoing regulatory
measures in place to prevent BSE contamination of U.S. food and food
products since 1989. Following the identification in a Washington state
dairy herd of the BSE-positive cow imported from Canada, the USDA has
issued four new regulations containing additional safeguards to further
minimize risk for introduction of the BSE agent into the U.S. food
supply. These safeguards include:
- A ban on use of live, but non-ambulatory cattle from entering
the human food supply
- A ban on use of organs, from cattle older than 30 months, in
which infectious prions occur and the tonsils and small intestine of
cattle of all ages for human food
- Restrictions on techniques to mechanically remove meat from
bones, and
- Meat from tested animals will not be certified as
USDA-inspected until test results are final.
See the USDA website www.usda.gov for further information.
FDA
fully supports the safety policies announced by the USDA, which build
on the principles and procedures that FDA and USDA have developed since
1989. These protective measures will add an additional layer of
protection for the American public.
FDA
will fulfill its increased responsibilities for protecting the safety
of the food and animal feed supply.
Is cow's milk a source of BSE?
Scientific
research indicates that BSE cannot be transmitted in cow's milk, even
if the milk comes from a cow with BSE.
Is the food in the U.S. likely to be a BSE risk to consumers?
FDA
and other federal agencies have had preventive measures in place to
reduce the U.S. consumer's risk of exposure to any BSE-contaminated
meat and food products. Since 1989, the USDA had prohibited the
importation of live animals and animal products from BSE-positive
countries. Since 1997 the FDA has prohibited the use of most mammalian
protein in the manufacture of ruminant feed. FDA continues to implement
policies to keep safe all FDA-regulated products, including food, food
ingredients, dietary supplements, drugs, vaccines, and cosmetics from
risk of any BSE-contaminated bovine material.
When and how did BSE in cattle occur?
BSE
in cattle was first reported in 1986 in the United Kingdom (UK). The
exact origins of BSE remain uncertain but it is thought that cattle
initially may have become infected when fed feed contaminated with
scrapie-infected sheep meat-and-bone meal (MBM). Scrapie is a prion
disease in sheep similar to BSE in cattle. The scientific evidence
suggests that the U.K. BSE outbreak in cattle then was expanded by
feeding BSE-contaminated cattle protein (MBM) to calves. The definitive
nature of the BSE agent is not completely known. The agent is thought
to be a modified form of a protein, called a prion, which becomes
infectious and accumulates in neural tissues causing a fatal,
degenerative, neurological disease. These abnormal prions are resistant
to common food disinfection treatments, such as heat, to reduce or
eliminate their infectivity or presence. It is important for consumers
to know that BSE, like other forms of Transmissible Spongiform
Encephalopathy (TSE), is not a communicable disease- most TSEs are not
spread easily between animals or to humans. Research is ongoing to
better understand TSE diseases and the nature of prion transmission.
Is BSE in cattle the same disease as CWD in deer and elk in
the U.S.?
BSE
is a Transmissible Spongiform Encephalopathy (TSE), a family of similar
diseases that may infect certain species of animals and people such as
scrapie in sheep and goats, bovine spongiform encephalopathy (BSE) in
cattle, chronic wasting disease (CWD) in deer and elk, and
Creutzfeldt-Jacob disease (CJD) in people.
To
date, there is no scientific evidence that BSE in cattle is related to
CWD in deer and elk. Research is continuing but there is no evidence
that either BSE or CWD can be transmitted between cattle, deer, or elk.
FDA is working closely with other government agencies and the public
health community to address CWD in wild and domesticated deer and elk
herds. Wildlife and public health officials advise people not to
harvest, handle, or consume any wild deer or elk that appear to be
sick, regardless of the cause, especially in those states where CWD has
been detected.
What countries have reported cases of BSE or are considered
to have a substantial risk associated with BSE?
These
countries are: Albania, Austria, Belgium, Bosnia-Herzegovina, Bulgaria,
Croatia, Czech Republic, Denmark, Federal Republic of Yugoslavia,
Finland, France, Germany, Greece, Hungary, Ireland, Israel, Italy,
Liechtenstein, Luxembourg, former Yugoslavia Republic of Macedonia, The
Netherlands, Norway, Oman, Poland, Portugal, Romania, Slovak Republic,
Slovenia, Spain, Sweden, Switzerland, Japan, and United Kingdom (Great
Britain including Northern Ireland and the Falkland Islands).
Canada
(May 2003) and the U.S. (December 2003) each have recently reported one
BSE-positive cow but remain countries considered to have a low risk.
The U.S. BSE-positive cow reported in December 2003 was confirmed to
have been imported from Canada in 2001.