What is Bovine Spongiform Encephalopathy (BSE)?
Bovine Spongiform Encephalopathy, or BSE, is a progressive, fatal disease of the nervous system of cattle. It is one member of a family of diseases known as transmissible spongiform encephalopathies (TSEs). Other TSEs include scrapie in sheep and goats, Chronic Wasting Disease (CWD) in deer, elk and moose, and Creutzfeldt-Jakob Disease (CJD) in humans.
What Causes BSE?
Although the exact cause of BSE is unknown, it is associated with the accumulation of abnormal or misfolded proteins, called BSE prions, in the brain. There is no treatment or vaccine currently available for the disease.
What are the Symptoms of BSE?
Because this is a slow developing disease, cattle with BSE may not show any signs of the disease for up to three to six years after they have been exposed to BSE prions. Symptoms are variable but always progressive and may include, nervous or aggressive behaviour, abnormal posture, incoordination, difficulty standing, decreased milk production, and weight loss. These symptoms may progress for up to six months until the animal dies.
How is BSE Transmitted?
BSE is not a contagious disease. Research indicates that the only risk factor for the spread of BSE is through feeding cattle meat and bone meal (MBM) derived from BSE-infected cattle. BSE prions are resistant to normal inactivation procedures, such as disinfectants and heat. BSE prions are not completely destroyed by the rendering process.
BSE is not contagious and cannot be transmitted through animal-to-animal contact. Nor are BSE prions present in milk or dairy products.
How is BSE Diagnosed?
BSE is a federally reportable disease in Canada, under the authority of the Health of Animals Act and also is provincially reportable under the Alberta Animal Health Act. Suspected neurological cases of BSE must be reported to the Canadian Food Inspection Agency (CFIA).
There is no test to diagnose BSE in live animals. The disease can only be confirmed by testing the animal's brain after death. Immunohistochemistry (IHC) is the international gold standard for confirmatory testing. This procedure takes a few days before results are available. The CFIA has approved a number of rapid (screening) tests for BSE, which significantly decrease the testing time. All tests producing a reaction are confirmed by IHC (and other methods) at CFIA's National and International Reference Laboratory for BSE in Lethbridge, Alberta (Canada).
Do We Have BSE in Canada?
Canada has had 19 BSE cases in cattle born in Canada. In all cases, no part of the animal entered the human food supply or animal feed chain. In addition, in 1993 BSE was found in a purebred beef cow which was imported from Great Britain in 1987. Also, in December 2003, a dairy cow which was diagnosed with BSE in the United States, originated from a farm in Alberta. In all cases, the CFIA located the farm of origin, conducted an epidemiological investigation and depopulated cattle of the same birth cohort (those born within 12 months of the infected animal) of the positive animal. None of the birth cohorts have tested positive to date.
Of the 19 cases reported in Canada, 14 of them have been diagnosed in Alberta, where they were sampled by veterinarians and submitted for testing under the Canada and Alberta BSE Surveillance Program (CABSESP).
What are the Trade Implications of BSE?
The Office International des Epizooties (OIE), the world animal health organization, has developed criteria to classify each country, based upon their risk for BSE. As of May 2007, Canada is classified as a country with "controlled" risk for BSE. The OIE-BSE Code provides guidelines for other countries to use in determining their import policies.
As a result of the first Canadian-born case of BSE reported in May 2003, over 30 countries, including the United States (US), placed trade restrictions on beef exports from Canada. In August 2003, the US began allowing whole-muscle cuts from Canadian cattle less than 30 months of age into their country. On July 13, 2005 the US border opened to Canadian ruminants under 30 months of age.
Canada implemented a number of mitigation measures to prevent infected material from entering the feed chain, such as the enhanced feed ban, which eliminates the possibility for any BSE prion to be incorporated in any animal feed, including pet food and fertilizers. Other important mitigation measure is the removal from carcasses of possibly infected nervous tissue, or Specified Risk Material (SRM). By doing this, 99.9% of prions are eliminated from the carcasses if they are contaminated. The role of BSE surveillance is to confirm that these mitigation measures are effective by detecting a progressively reduced prevalence of BSE in our cattle population.
Do Other Countries Have BSE?
Other countries known to have native cases of BSE include, the United Kingdom, Germany, France, Portugal, Denmark, Spain, Italy, Switzerland, the Netherlands, Finland, Greece, Belgium, Austria, Czech Republic, Ireland, Israel, Liechtenstein, Slovakia, Slovenia, Luxembourg and Japan.
What is Being Done to Prevent BSE from Becoming Established in Canada?
Canada has implemented a number of precautions to prevent the spread of BSE and to protect public health. These measures include the following:
- In 1990, Canada made BSE a reportable disease. Any suspect cases of BSE must be reported to the CFIA, who is responsible for control and eradication of the disease, under the authority of the Health of Animals Act.
- Canada only allows importation of live ruminants, their meat and meat products from countries that Canada considers to effectively control BSE.
- Canada has not imported European ruminant-derived MBM for use in livestock feeds for more than a decade. In December 2000, Canada banned the import of rendered animal material from any species from any country that Canada does not recognize as free of BSE.
- In August 1997, Canada introduced a ruminant-to-ruminant feed ban, meaning that rendered protein products from ruminant animals (cattle, sheep, goats, bison, elk or deer) cannot be fed to other ruminants.
- In July 2003, Canada implemented the removal of specified risk material (SRM) from the human food chain. SRMs are tissues that, in BSE-infected cattle, contain more than 99% of BSE infectivity, and include brain, spinal cord, trigeminal and dorsal root ganglia, eyes, tonsils in animals over 30 months of age and the intestine in cattle of all ages. Alberta immediately implemented this SRM ban at all provincially licensed abattoirs and meat processing facilities in July 2003.
- In July 12, 2007, the CFIA announced amendments to the federal regulations prohibiting SRMs from being used in all animal feed, including pet food and fertilizers.
- The implementation of the Canadian Cattle Identification Program (CCIP) makes it possible to trace individual animals to their herd of origin. In 2004, the program was expanded to include bison and sheep.
- In Alberta, a robust traceability system is made up of three key components: premises identification, animal identification and animal movement tracking. Together, these enable the government or other emergency management officials to pinpoint and isolate specific sites of concern and target resources in the event of a threat to animal or human health as a result of a natural disaster. The integrity of this system also translates into opportunities for Alberta's livestock and meat industries to differentiate their products.
Canada is continually assessing international scientific information as it becomes available and modifying policies, as required.
What is the Purpose of Testing Cattle for BSE?
There are two primary reasons why Canada must conduct surveillance for BSE. First, BSE surveillance is a measure of the effectiveness of the precautionary processes Canada has implemented since 1990 to prevent the spread of BSE. For example, the ruminant-to-ruminant feed ban implemented in 1997.
BSE surveillance also facilitates an estimate of the prevalence of BSE in Canada's adult cattle herd. This is important because it allows Canada to improve or maintain its status with the OIE and the international community.
Canada has conducted surveillance for BSE since 1993. ARD has participated in the national BSE surveillance program since 1996. Alberta enhanced its BSE surveillance in 2002 by targeting cattle over 18 months of age that exhibited neurological signs, were downers, or were condemned at provincially licensed abattoirs, were presented for emergency slaughter, or died for no apparent reason. After that time, the CABSESP has evolved according to changing international, industry and cattle conditions. ARD shares information on an ongoing basis with the CFIA on BSE surveillance.
In 2004, the CFIA announced enhanced targets for BSE testing, 8,000 cattle in 2004, increasing to 10,564 annually. The Canada-Alberta BSE Surveillance Program (CABSESP) was initiated in September 10, 2004 to increase the number of high-risk Alberta cattle tested for BSE as part of Canada's BSE surveillance initiative. From September 2004 to April 2015, the CABSESP tested approximately 156,000 samples for BSE in Alberta.
What is the Canada-Alberta BSE Surveillance Program?
The Canada and Alberta BSE Surveillance program was initiated (retroactive to July 1, 2004) as a response from Alberta to help meet national and international animal health standards. The minimum numbers suggested by CFIA for testing in Alberta were very soon surpassed by Alberta, which tested 11748 animals in 2004.
The Canada-Alberta BSE Surveillance Program provides reimbursement to producers for the costs associated with holding the carcass pending a negative test result and for appropriate disposal. Producers are reimbursed $75 from Federal funds for each sample submitted to the CABSESP. Veterinarians are paid for the farm visit, clinical and/or postmortem examination of animals and the costs associated with filling in the application forms and submitting testable samples from eligible cattle for BSE testing to either the ARD laboratory in Edmonton or the CFIA-BSE laboratory in Lethbridge. Provincial abattoirs are no longer in the program. The program has undergone a number of changes towards improving its capability and efficiency.
Which Cattle are Eligible Under the Program?
Eligible cattle include those which fall into one of the following categories : 1) neurologicals. 2) downers, 3) dead, 4) diseased or 5) distressed. Cattle eligibility must be determined by a certified veterinarian. Clinical BSE suspects must be reported to a CFIA district veterinarian. If a producer suspects he/she has a qualifying animal, they should contact their closest certified veterinarian.
Why Don't We Test All Cattle for BSE?
OIE guidelines are based on science and recommend BSE surveillance be targeted to those groups of cattle most likely to test positive, or, in other words, the animals in the age frame and clinical category that is most likely to develop BSE. It takes between two and eight years following exposure to BSE before cattle develop clinical disease. In the United Kingdom, of 180,000 cattle found to be positive for BSE, only 0.05% were 30 months of age or less and 0.006% were 24 months of age or less. Over 80% of cattle slaughtered in Alberta are less than 18 to 22 months of age and are, therefore, extremely unlikely to test positive. Public health is not protected by BSE surveillance; rather it is protected by the removal of SRMs from the human food chain.
Is Alberta's Beef Safe?
Yes, Alberta beef and dairy products are safe for consumption. Alberta's food safety system is among the best in the world. Most beef comes from animals that are less than 30 months of age, before BSE is a problem. The prevalence of BSE is extremely low in Canada and SRM removal eliminates more than 99% of the BSE infectivity if the animal was affected.
What are the Responsibilities of Beef and Dairy Producers?
- Anyone suspecting that an animal that is having neurological signs should contact his or her veterinarian to diagnose the condition. Cattle suspected of having BSE must be reported to the CFIA.
- Producers who believe they have an animal that is eligible under the Canada-Alberta BSE Surveillance Program should contact their local certified veterinarian. Failure by Canada to test an adequate number of these cattle may jeopardize market access of ruminants or ruminant products.
- Producers are responsible for checking feedbags carefully for the label "Do not feed to cattle, sheep, deer or other ruminants". Such feed may contain material that is prohibited for ruminants. If you mix feed on your farm, ensure that you follow directions and prevent cross contamination of ruminant feeds with feed that is intended for non-ruminants (horses, hogs, poultry).
- Livestock producers should purchase only feeds identified by retailers or manufacturers as free of SRM.
- Producers must keep records of feed and feed ingredient purchases that include: the supplier's name and address, the date of purchase; and the amount purchased.
- Avoid disposing of old feed in grassing areas.
- When there is a confirmed case of a disease such as BSE, accurate records become vital for tracing animal movements, animal contacts and finding the herd of origin, offspring, past herd mates and any connection to other herds. The sooner these animals are identified, the sooner the investigation can be completed. The seriousness of one case of BSE is evident. Accurate records are essential to minimize the impact of detecting a case of BSE.
For further information about BSE, please view:
CFIA's BSE Information page