Bovine Spongiform Encephalopathy (BSE)
BSE, widely known as "Mad Cow Disease", is a fatal disease of cattle first recognized in the United Kingdom in 1986. Most research suggests an abnormal protein, known as a prion, causes BSE. Scientific evidence shows the same disease agent that causes BSE in cattle also causes the new human disease, variant Creutzfeldt–Jakob disease. BSE spreads in cattle primarily through animal feed containing processed ruminant products. Cattle infected with BSE take 2 to 8 years before showing signs of disease, which include changes in temperament such as nervousness or aggressiveness, and progressive incoordination. November 19, 2007 – US Border is reopened to imports from Canada.
Information About BSE
BSE in Canada
December 18, 2007 – BSE case confirmed in 13–year–old Alberta beef cow
OTTAWA – The Canadian Food Inspection Agency (CFIA) has confirmed the diagnosis of bovine spongiform encephalopathy (BSE) in a 13–year–old beef cow from Alberta. The animal's carcass is under CFIA control, and no part of it entered the human food or animal feed systems. This animal was born before the implementation of Canada's feed ban in 1997.
An epidemiological investigation, directed by international guidelines, is underway to identify the animal's herdmates at the time of birth, and the pathways by which it might have become infected. All findings will be publicly released once the investigation concludes.
November 19, 2007 – The U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) expanded the list of allowable imports from countries recognized as presenting a minimal risk of introducing bovine spongiform encephalopathy (BSE) into the United States. Currently, Canada is the only minimal-risk country designated by the United States. With the publication of this rule, exports of meat and meat products from older Canadian animals will be allowed into the U.S.
August 23, 2006 – BSE confirmed in eight to ten–year–old beef cow from Alberta.
July 13, 2006 – BSE confirmed in a 50–month–old dairy cow from Alberta.
The 50–month old dairy cow died and was retained on farm. No part of the carcass entered the human food or animal feed systems; the entire carcass was incinerated. Given the affected animal's age, it was exposed to BSE after Canada's feed ban was implemented in 1997.
July 4, 2006– BSE confirmed in a mature cross–bred beef cow from Manitoba.
The cow was at least 15 years of age, born well before the 1997 introduction of Canada's feed ban. Investigators are attempting to locate the birth farm, the animal's herdmates and feed to which it may have been exposed at a young age. Given the animal's age, there may be few surviving animals and limited sources of information. A calf born to the affected animal in 2004 is also being traced.
April 16, 2006– BSE Case Traced to British Columbia, Canada
On April 16, 2006, BSE was confirmed in a 6–year–old dairy cow from British Columbia, Canada. The Canadian Food Inspection Agency investigated 148 animals and the feed sources used on the affected animal's birth farm. The formulation, production, transportation and storage of these feeds were reviewed.
January 23, 2006 – BSE Case Traced to Alberta, Canada
On January 23, 2006, the CFIA confirmed that a six–year–old crossbred cow was infected with BSE. The animal exhibiting symptoms of BSE was tested as part of Canada's National Surveillance program for BSE. No part of the animal entered the human or animal food chain.
The investigation conclusions:
- The cow gave birth twice in two years prior to clinical disease onset. The 2005 offspring was found on the farm of origin, euthanized, sampled and tested negative. The 2004 offspring had been sold and was determined to have died on premise during the first year of life.
- Identified 38 birth cohorts were euthanized and tested negative for BSE.
- Feed investigation revealed one of two suppliers produced feeds for ruminants as well as feeds for non–ruminant species. The feeds produced for non–ruminant species included material prohibited for use in ruminant feeds. This manufacturing facility had procedures in place to minimize opportunities for contamination of ruminant feeds with prohibited material and comply with the regulatory requirements of the feed ban.
January 11, 2005 – BSE Case Traced to Alberta, Canada
On January 11, 2005, the CFIA confirmed that a six–year–old Charolais cow was infected with BSE. The herd of origin was in Alberta. No part of the animal entered the human or animal food chain.
The investigation conclusions:
- The cow gave birth twice in two years prior to her death. One calf was slaughtered in Canada in the fall of 2003 and the other, born in 2004, was located in a feedlot, euthanized and incinerated.
- Identified 41 birth cohorts were euthanized and tested negative for BSE.
- Feed investigations revealed nine commercial formulations found on the farm of origin were examined as possible routes of Meat and Bone Meal (MBM) exposure. Of the nine potentially contaminated sources, four feeds were manufactured by feed mills in Alberta or Saskatchewan. The feed mills manufactured non–ruminant feeds containing Meat and Bone Meal (MBM), which could have caused cross contamination resulting in BSE infection.
January 2, 2005 – BSE Case Traced to Alberta, Canada
On December 17, 2004, a private veterinarian in Alberta euthanized and sampled an eight–year–old Holstein cow for BSE. Infection was confirmed on January 2, 2005. No part of this animal entered the human or animal food chain – the CFIA incinerated the entire carcass.
The investigation conclusions:
- Infected animal produced three offspring prior to diagnosis. The 2002 heifer calf was sold to a feedlot and slaughtered in March 2004. The 2003 bull calf was slaughtered on farm for personal use. (The meat had not been consumed and as a precaution was incinerated.) The final calf was stillborn in 2004.
- Records from the farm of origin identified 135 birth cohorts. Investigators traced 122 cattle to slaughter and/or death. Five cattle were slaughtered in the US. Four additional cattle may also have been slaughtered in the US.
- The infected cow was born on October 5, 1996 – before the Canadian Feed Ban began. The animal was fed a ration (containing meat and bone meal) manufactured in March 1997. CFIA concluded that the animal was most likely exposed to BSE through consumption of this feed.
December 2003 – BSE Case Traced to Alberta, Canada
On December 25, 2003, the United States Department of Agriculture (USDA) confirmed BSE in a 6–year–old Holstein cow slaughtered in the state of Washington. The infected cow entered the US in 2001, as part of a shipment of 81 animals from a source herd in Alberta, Canada. The downer cow was sent to slaughter and tested for BSE as part of the USDA's targeted BSE surveillance program.
The investigation conclusions:
- The positive cow had given birth to two live offspring in the US. A bull calf born in November 2003 was sold to a calf–raising facility in Washington and the other calf, a yearling heifer, was present in the Washington herd. These animals were identified and destroyed.
- Of the 81 animals imported with the index cow from Canada, 25 cattle were classified as high–risk birth cohorts. USDA accounted for 14 of the 25 animals.
- A total of 255 cattle were depopulated from 10 premises on which one or more source herd animals were found. All 255 tested negative for BSE.
- Affected animal was not indigenous and her exposure to BSE causative agent occurred in Canada.
May 2003 – BSE Case Traced to Canada
On May 20, 2003, Canada received confirmation from World Reference Laboratory at Weybridge, United Kingdom, that a 6–year–old Angus beef cow tested positive for BSE. The cow was born in northern Saskatchewan in March 1997. The cow was detected as part of Canada's ongoing BSE surveillance program. Alberta agricultural officials tested a cow that had been condemned at slaughter. No meat from the cow entered the human food chain.
The remains of the infected cow were sent to a rendering plant in Alberta, Canada. Rendering uses the discarded portions of animal carcasses to produce two products, "meat and bone meal" and "tallow." The CFIA traced possible rendered products from the affected cow.
The investigation conclusions:
- Animal DNA testing confirmed the herd of origin.
- The case farm, the potential source farms, and other farms at risk were placed under quarantine. The entire affected herd has been slaughtered and has tested negative for BSE. Targeted animals of interest, including birth cohorts, were included in this population of slaughtered animals. More than 2,800 animals were depopulated and tested negative in this investigation.
- The index animal produced two calves prior to diagnosis. The two animals were located in the US and were euthanized and tested negative for BSE.
- The feed investigation focused on three commercial sources of protein available to dairy cattle on the birth–herd premises. One of the rations could have contained contaminated MBM.
USDA Minimal Risk Rule Enables US to Open Canadian Border
The USDA published a final rule classifying regions as "minimal risk for introducing BSE into the U.S." on January 4, 2005. The rule aims to continue to protect the U.S. from BSE while removing unnecessary restrictions on trade in ruminants, their products and byproducts. This rule recognizes Canada as the first country to be classified as a minimal–risk region after diagnosing BSE. Other regions that meet the minimal–risk conditions in the future will be classified through rulemaking and a risk assessment.
Other Links
- U.S. Secretary of Agriculture Statement regarding Ninth Circuit Courts Ruling
- Johanns announces next steps for Importation
- BSE in North America (Canada)
BSE in Europe
Numerous laws have been implemented to protect the public against the risks from BSE. Member States must ensure full implementation of all European Union rules relating to BSE. On May 22, 2001, the European Parliament and Council adopted Regulation (EC) 999/2001, which were rules for the prevention, control and eradication of certain transmissible spongiform encephalopathies.
Since July 2001, member states have carried out and expanded surveillance programs on BSE in cattle. The surveillance involves BSE suspect clinical cases; active surveillance of healthy slaughtered cattle and high–risk animals such as fallen stock. The main purpose of the surveillance program is to determine prevalence of BSE in the Member States. The implementation ensures that no BSE cases are being slaughtered for human consumption. With the removal of risk animals and destruction of specified risk materials, human health is protected.
The overall incidence of BSE in the European Union is falling. In a few Member States the number of cases is still rising in 2002; likely due to the expansive BSE testing since July 2001.
Current testing program for BSE in the EU
In addition to the mandatory examination of all animals showing signs suggestive of BSE, rapid post–mortem testing for BSE must, as of January 1, 2001, be carried out on:
- All bovine animals over 24 months of age slaughtered as emergencies or showing signs of any kind of illness at the ante mortem inspection in the slaughterhouse.
- All bovine animals over 30 months of age subject to normal slaughter for human consumption. Sweden is allowed to test only a random sample.
- All fallen stock cattle over 24 months of age, which have died or been killed on the farm or in transport, and are not slaughtered for human consumption.
EU Preventing the Introduction and Spread of BSE
- April 9,1990, all animals presented for slaughter were required to be inspected by veterinarians to ensure that suspected cases do not enter the food and feed chains;
- July 1994, the feeding of mammalian meat and bone meal (MBM) to cattle, sheep and goats, was banned;
- January 1,1995, high processing standards were implemented for the treatment of ruminant animal waste. Standards were re–enforced on April 1, 1997, through implementation of pressure–cooking regulation (133 °C/3 bars/20 minutes) for all mammalian waste used for the production of MBM,
- In July 2001, animals with a high probability of receiving the same potentially infected feed as a BSE case were culled and destroyed. Animals of the same age from the same herd (cohort animals) were likely to have received the same potentially infected feed and were also culled. In addition, the latest born offspring to female BSE cases must be culled, due to potential maternal transmission.
- In October 2000, the EU mandated all specified risk materials (SRMs like spinal cord, brain, eyes, tonsils, parts of the intestines) be removed from cattle, sheep and goats from the human and animal food chains throughout the EU. In March 2001, the list of SRM was extended to include the entire intestine of bovines and vertebral column.
- January 2001, a targeted testing program for BSE focusing on high–risk animals was implemented.
- January 2001, a complete ban on the use of processed animal protein in feeds for any animals farmed for the production of food
Links
BSE in North America
To date, there have been fifteen Bovine Spongiform Encephalopathy (BSE) cases diagnosed in North America. See North America Summary, December 18, 2007 (PDF 47 KB).
- 1993 – United Kingdom (UK) import killed in Canada
- May 2003 – Adult cow traced to Saskatchewan, Canada
- December 2003 – Cow killed in State of Washington traced to Alberta, Canada
- January 2005 – Two cows traced to Alberta, Canada
- June 2005 – Adult cow born in Texas, USA
- January 2006 – Adult cow traced to Alberta, Canada
- March 2006 – Cow killed in Alabama, USA
- April 2006 – Cow from British Columbia, Canada
- July 2006 – Cow from Manitoba, Canada
- July 2006 – Cow from Alberta, Canada
- August 2006 – Cow from Alberta, Canada
- February 2007 – Bull from Alberta, Canada
- May 2007 – Dairy cow from British Columbia, Canada
- December 2007 – Beef cow from Alberta, Canada
The current hypothesis is that BSE entered North America through cattle imported from the UK during the 1980’s. There were 182 UK cattle imported directly into Canada and 300 imported in the US from 1982 to 1990. Following their arrival into North America, the UK imports became members of Canada or US national cattle herds.
Since the 1980’s, both the US and Canada have implemented preventative measures to ensure cattle and human health.
BSE in the United Kingdom
BSE was first diagnosed in the U.K. in November 1986 at the Central Veterinary Laboratory, Weybridge. The initial two BSE positive cows originated from two herds in different parts of England, but showed the same abnormal neurological symptoms.
In response to the emergence of BSE, epidemiological studies were started in April 1987. Epidemiogical analysis showed the disease was spread by contaminated feed.
The epidemic reached its peak early in 1993. Since then the number of cases has decreased. In 2003, there had been around 25 new BSE suspect cases per week; at the peak of the epidemic in 1992–93 there were over 1000 suspected cases per week. The youngest animal affected was 20 months and the oldest was 18 years old. Detailed figures on the progress of the disease are available.
How the UK Responded to BSE
In 1988, to ensure reporting, BSE was made notifiable in the U.K. All diagnosed clinical cases were destroyed. Producers were paid about £600 in indemnity. The payment was more than the animal was worth at slaughter, therefore was an incentive to improve reporting. These animals showing signs of the disease were banned from the human food chain to protect public health (no sick animals can be slaughtered for human food).
By 1994, all mammalian proteins were banned from ruminants. In March 1996, the U.K. banned mammalian MBM to all farmed livestock – including chickens, pigs, horses, fish – to avoid any cross contamination. Mammalian protein in forms other than MBM was permitted for swine and poultry feeding.
In 1996, all cattle over 30 months of age were banned from the human food supply. When presented for slaughter, these animals were redirected to rendering channels. Producers are paid about £400 (meat price) for these cattle. Because rendered product was of no economic use it was destroyed by incineration. All processes were tightly controlled to ensure product was not used.
Incinerators were built to burn BSE carcasses. Each incinerator held 4 cows, and burned at >1000C. It took 2 hours to burn to ash with periodic stirring. Ash was removed, tested for proteins, and disposed of in a landfill. Any sediment and effluent was recycled back through the furnace. The emissions were highly controlled.
United Kingdom BSE Links:
BSE in the United States
On March 13, 2006, BSE was confirmed in a non–ambulatory,
approximately 10–year old crossbred beef cow sampled on a farm in
Alabama by a private veterinarian. No part of the animal entered the
human or animal food chain. The cow had resided on the farm for less
than a year. The investigation has been completed. More
...
On June 24, 2005, BSE was confirmed in a cow slaughtered in November 2004. The cow was sampled for BSE at a pet food facility in Texas. DNA tests confirmed that the approximately 12–year old Brahma–cross cow was born and raised in Texas. The herd was quarantined and cattle that were in a similar birth group and/or ate the same feed as the infected cow were traced and removed.
The first case detected in the U.S. was confirmed on December 25, 2003, by The Veterinary Laboratories Agency in Weybridge, England. This case was in an adult Holstein cow slaughtered in the State of Washington. The epidemiological investigation and DNA test results confirmed the infected cow was not indigenous to the U.S., but was born and became infected in Alberta, Canada. Animals with known or potential risk for having been infected with the BSE agent and all progeny from the index cow in the U.S. were depopulated. All carcasses were properly disposed of in accordance with Federal, State, and local regulations.
Links for US Case:
- USDA BSE information
- USDA Food Safety Inspection Service BSE site
- FDA BSE link
- USDA BSE Response Plan Summary (PDF 48 KB)
- Canadian Food Inspection Agency BSE Web Page
- Producer Guide August 2007 (PDF 184 KB)
- BSE Inconclusive test results July 2004 (PDF 35 KB)
- USDA Surveillance Fact Sheet June 2004 (PDF 42 KB)
- BSE Prevention Brochure January 2004 (PDF 42 KB)
- BSE Prevention Feed Poster March 2006 (PDF 99 KB)
USDA announces BSE test results and new BSE confirmatory test Protocol
WASHINGTON, June 24, 2005 –– Agriculture Secretary Mike Johanns
today announced that the U.S. Department of Agriculture has received
final test results from The Veterinary Laboratories Agency in
Weybridge, England, confirming that a sample from an animal that was
blocked from the food supply in November 2004 has tested positive for
bovine spongiform encephalopathy (BSE)...
more 
"
- The IHC Test Variables ––APHIS Fact Sheet (PDF)
- BSE Confirmatory Testing––APHIS Fact Sheet (PDF)
- BSE Testing, Step by Step––APHIS Fact Sheet (PDF)
Significant New USDA Actions
On December 30, 2003 the USDA announced additional safeguards against BSE:
- Ban non–ambulatory cattle from the human food chain
- Ban specified risk materials (skull, brain, trigeminal ganglia, eyes, vertebral column, spinal cord and dorsal root ganglia) of cattle over 30 months of age and a portion of the small intestine of cattle of all ages from human food
- Hold cattle tested for BSE at slaughter until confirmed negative for BSE
- Ban neural tissue in "advanced meat recovery" products labeled "meat"
- Ban air–injection stunning
- Ban mechanically separated meat in human food
- Implement a national animal identification system.
Contact us for more information:
California Department of Food and Agriculture
Animal Health and Food Safety Services, Animal Health Branch
1220 N Street, Room A-107
Sacramento, California 95814
Telephone: (916) 654-1447
Fax: (916) 653-2215
or send an email to: ahbfeedback@cdfa.ca.gov