Canada implemented a national bovine spongiform encephalopathy (BSE) surveillance program in 1992. In 2003, the Government announced that the number of annual BSE samples tested through this program would be increased. The level and design of BSE testing in Canada has always been, and continues to be, in full accordance with the guidelines recommended by the World Organisation for Animal Health (WOAH); founded as Office International des Épizooties (OIE).
Surveillance is one of many BSE-related actions Canada has implemented to manage BSE. The program tests a sample of animals from the national cattle herd and focuses on higher-risk animals that are most likely to be affected by the disease. The surveillance program's objectives are to determine and monitor the level of BSE present in Canada and to confirm the effectiveness of the suite of measures Canada has implemented to protect human and animal health from the disease.
No validated live animal test for BSE currently exists. Accordingly, testing for BSE can only be done on the brains of dead animals. Brain samples are screened using rapid tests that accurately and quickly detect a BSE positive sample nearly 100% of the time. Rapid tests can, in rare cases, react when a sample is not infected with BSE. These are known as "inconclusive" results. All samples that yield inconclusive results using a rapid test are sent to the Canadian Food Inspection Agency (CFIA) laboratory in Lethbridge, Alberta for confirmatory testing.
The number of samples tested is subject to change as new laboratory results are provided.
"Samples tested" indicates the number of samples submitted or being submitted to provincial or federal laboratories. Each sample represents 1 animal. Monthly values represent only the number of samples obtained in that month. "Year to date" values represent cumulative samples.
In January 2004, the Government of Canada announced that it would enhance its BSE surveillance testing to at least 8,000 cattle during the first year and to 30,000 per year in subsequent years to calculate the prevalence of BSE in Canadian adult cattle. The level and design of this enhanced program continues to be in full accordance with the guidelines recommended by the WOAH.
BSE surveillance samples come from a variety of sources, including the farm, federal, provincial and territorial abattoirs, rendering and deadstock operations, veterinary practitioners, and university and provincial veterinary diagnostic laboratories.
Positive
Positive samples are those whose positive reaction has been confirmed by immunohistochemistry (IHC), or by immunoblot analyses in low-quality samples or samples with a negative reaction to IHC.
