MAD COW DISEASE or Bovine spongiform Encephalopathy continued
Bovine Spongiform Encephalopathy (BSE) or Mad cow disease is considered a transmissible spongiform encephalopathy (TME) similar to chronic wasting disease (CWD) in deer, scabies in sheep, and/or Creutzfeldt-jakob disease (vCJD) in humans.
But like.. what is it? LETS BREAK IT DOWN.
Bovine = cattle
Spongiform = resembling a sponge
Encephalopathy = disease of the brain
BSE isn’t caused by bacteria or a virus; it’s caused by prions. Prions are misfolded proteins that accumulate in the central nervous system. Our bodies are made up of proteins that are folded a certain way to perform everyday functions. When misfolded, they are unable to do what they need to do and this can have catastrophic effects. If these prions interact with normal folded proteins, it causes them to misfold too.
BSE was first discovered in the UK in 1986 and >95% of positive cases in the world have been from there. This is why you can’t donate blood if you’ve spent more than 3 months in UK between 1980 and 1996. BSE is not a contagious disease. There is no evidence that BSE or other transmissible spongiform encephalopathies can be transferred to people through direct contact with the animal or by eating meat from a BSE positive animal. But, ingestion of infected nervous tissue is associated with increased risk of Creutzfeldt-jakob disease (vCJD) in humans. This is why the nervous tissue or “specified risk materials” are completely removed from the food chain in higher risk animals.
What are specified risk material (SRM)?
These are parts of the animal where prions would accumulate if an animal is infected with BSE
The skull, brain, trigeminal ganglia (nerves attached to the brain), eyes, tonsils, spinal cord, and dorsal root ganglia (nerves attached to spinal cord) of cattle 30 months or older; and the distal ileum (small intestine) of cattle of all ages
How is BSE transmitted in cattle?
Feed contaminated with OR cattle in contact with SRM material infected with BSE
Very rarely: sporadic spontaneous infection or cow to calf
What are the signs cows show?
Typically, in cattle between 4-6 years old (because of the long incubation period) although can be older
Hypersensitivity (more common)
Excessive salivation, increased head rubbing, vocalization, weight loss, decreased milk output, incoordination, and/or tremors
Could I get BSE from eating animal products?
No. BSE prions have not been shown to accumulate in the muscle or milk. Unless you are eating the SRM (products removed from the food chain) from an BSE infected animal, there is no evidence that humans can acquire the disease (or other TSE) from eating animal products
Humans cannot get BSE but they can get a variant of the disease (vCJD) if they eat contaminated SRM material from infected cattle
What is Canada to ensure our food is safe? (see my previous post for explanation)
BSE surveillance
Enhanced feed ban
Canadian Cattle Identification Agency (CCIA)