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News Item
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May 27, 2003
BSE Update:
BOVINE SPONGIFORM ENCEPHALOPATHY (MAD COW DISEASE)
Manitoba Agriculture and Food
Veterinary Services Branch
545 University Crescent
Winnipeg MB R3T 5S6
WHAT WE KNOW:
About BSE
- Mad Cow Disease (Bovine Spongiform Encephalopathy - BSE) is a degenerative disease that affects the central nervous system of cattle.
- BSE is a slowly progressing, fatal, nervous disorder. The characteristic symptom is a staggering gait.
- BSE is believed to be linked to an abnormal form of a normal protein found in the body called prions. Prions do not contain DNA or RNA. Abnormal proteins are not broken down or changed by sterilization or cooking. Incineration and high concentrations of certain chemicals (formic acid, sodium hydroxide, sodium hypochlorite) can destroy them.
- Accumulation of this abnormal protein leads to a sponge-like appearance of the affected brain, causing neurological illness and death.
- BSE has a long incubation period of two to eight years.
- BSE is fatal for cattle within weeks to months of its onset (following incubation).
- Scientists have established that the BSE abnormal prion is found exclusively in cow brain, spinal cords, and specific lymphatic tissue. There is no test to diagnose BSE in live animals. It can only be confirmed by testing of the brain after death.
- Single-stomached animals such as horses, pigs, cats and dogs are not susceptible to BSE.
- Milk does not carry the disease.
About This Case
- The infected cow was a commercial Black Angus and was 6 years old.
- Twelve farms in Alberta, three in BC and two in Saskatchewan have been quarantined. The BC herds are under quarantine due to possible exposure to feed products made from rendered remains of the infected cow. The other fifteen herds are either trace-forward or trace-back herds with potential animal contact.
- The index herd was slaughtered and samples have been tested on all the cattle for BSE. The initial rapid test results were all negative. The confirmatory IHC tests are now being performed.
- All calves sold off the index farm in 2003 have also been slaughtered and are currently undergoing testing. In addition, one Saskatchewan herd has been destroyed and is likewise being tested. The cow's birth farm has not been determined; DNA testing of the cow and suspected sires is being performed. The infected cow's progeny are all being traced, destroyed, and tested.
- One other positive case for BSE was found in Canada in 1993. That animal had been imported from the UK. There were 186,000 positive cases in cattle in UK during the 90's.
- It took from January 31, 2003 until May 16, 2003 to get the results from the samples that were taken from the animal because it was condemned and sent for rendering. The tests on these animals have a lower priority than tests from carcasses that are waiting clearance to go to the food chain. Consequently, it took a long time for the lab to process that sample. As soon as the sample was tested and showed a positive result (the morning of Friday, May 16th), it was referred to CFIA for analysis at the lab in Winnipeg, with a confirmatory positive result obtained on May 18th. They then forwarded the sample to the World Reference Laboratory in Britain who again confirmed the disease on May 20th. The results were released on Tuesday, May 20th.
- It is highly unlikely that the infected cow got the disease from a deer with Chronic Wasting Disease, a related brain wasting disorder. Scientists at the world reference lab in the UK indicate that they are confident the cow is a classical BSE case, not some variant form. In US research studies, cattle are still normal 6 years after having been fed infected CWD brain material, and after being housed in the same enclosures with infected deer and elk.
About human health
- In 1996, researchers confirmed a new variant of Creutzfeld-Jacob Disease (CJD) now called vCJD. There is an apparent causal relationship between BSE and vCJD. Ingestion of beef products containing infected neurological tissue and/or lymphatic tissue is thought to be the route of spread of BSE to humans. This human disease takes several years to develop and has no cure. Approximately 150 people in the UK have died from this disease since the outbreak in the 90's.
- In Canada, human risk is very low since the infected animal did not enter the food chain.
About Rendering
- Rothsay is no longer able to handle bovine offal or deadstock through its rendering line. Rothsay will continue to pick up these products and deliver them to the Brady landfill for deep burial. This is a temporary arrangement - maximum two months.
- MAF, MB Conservation, MB Health, CFIA and the industry stakeholders are searching for alternate disposal options including incineration, composting, and burial in approved landfills.
- Rothsay will not pick up any autopsied carcasses from any location, and will not provide pick-up service to veterinary laboratories or to veterinary clinics. These organizations/individuals will be responsible for the appropriate disposal of these carcasses.
WHAT WE DON'T KNOW
About this case
- How did the infected cow get the disease?
- Do any other animals have the disease?
- Do the tests come back positive if the disease is in the incubation stage, or only if it is advanced?
- If there was feed contamination, how widespread was it?
- Can the disease be passed to offspring?
- Could this case have been caused by a spontaneous event?
WHAT IS BEING DONE?
In this case
- CFIA is the agency responsible for dealing with this crisis.
- CFIA has inspected the rendering plant, feed mills and laboratory in Alberta. They have examined facilities and records and are satisfied that the rules were followed
- CFIA is tracing the animal to its birth and following all offspring. Seventeen farms have been quarantined.
- The index herd, the 2002 calf crop, and one contact herd have been slaughtered. The index herd has tested negative for BSE.
The BSE Control Program in Canada
- 1990 - Canada banned the import of cattle from the UK and EU.
- 1997 - Canada banned the use of ruminant protein (cattle, sheep, goats, bison, elk, deer) in ruminant feed.
- Ruminant protein can be used in pet food or feed for chickens, pigs and horses. These animals are not at risk for BSE and cannot pass it to other animals.
- Canada only allows the importation of live ruminants from New Zealand, Australia and the US.
- Canada only permits the importation of meat and meat products from countries considered to be free of BSE
- BSE was made a reportable disease in 1990. Any suspect cases of BSE must be reported to a federal veterinarian.
- The US border has been closed for export of Canadian cattle.
- BSE surveillance system was put in place in 1992 and samples from the brains of over 10,000 cattle in Canada have been tested since then. In 2002, 3,770 were tested. The EU tests all cattle over 30 months of age at slaughter.
Contacts
Manitoba Government contacts for the BSE issue are as follows:
MAF - Dr. Allan Preston - 945-7650
MB Conservation - Al Beck - 945-8553
MB Health - Public Health - Dr. Joel Kettner - 788-6666
Food safety - Jim Drew - 788-6745
Manitoba Veterinary Medical Association - Dr. Lisa Sawka - 889-3110
Allan Preston, D.V.M.
Director
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