Swiss Cheese Brains and Stubborn Proteins
Picture this:
And so begins the saga of BSE - the infamous Mad Cow disease, the microscopic villain that turned quiet farms into detective scenes.
What It Is
Bovine Spongiform Encephalopathy (BSE) is caused by a prion.
A normal protein is like a well-behaved office worker:
- Comes to work folded correctly
- Does its job quietly
- Clock in, clock out
- No drama
Now…
A prion is the chaotic cousin who shows up to the office completely misfolded - like a shirt twisted inside-out and half tucked into the trousers.
But the worst part?
Suddenly half the office is wearing their clothes upside down, nothing gets done, and the entire office collapses into confusion.
It’s… well… rude.
What It Does and Why Pet Parents Should Care
In cattle, symptoms include:
- Unsteady gait
- Nervous or aggressive behaviour
- Difficulty standing
- Weight loss
- Decreased milk production
- Eventually, inability to move
In humans (variant Creutzfeldt-Jakob disease):
- Behaviour change
- Memory loss
- Poor coordination
- And sadly, rapid neurological decline
Why pet parents should care:
- The beef we buy
- The processing systems we trust
- The feeding rules for livestock
- The safety of animal-derived pet foods
The Discovery
Our story begins in the United Kingdom, 1980s.
Farmers started noticing cows acting like they’d wandered out of a Shakespearean tragedy - trembling, confused, collapsing.
“Like a sponge,” one of them said softly.
A mystery slowly untangled.
So… Where Did the First Prions Actually Come From?
Theory 1 - The Sheep Connection
- Itching
- Neurological decline
- And yes, sponge-like holes in the brain too
Theory 2 - A Spontaneous Mutation
Theory 3 - Changes in Rendering Practices
How It All Connects
Putting the puzzle pieces together:
- Scrapie prions existed in sheep for ages.
- Sheep tissues were processed into cattle feed.
- Rendering changes accidentally allowed prions to survive the process.
- Cows ate the contaminated feed.
- The prion adapted to the cow’s version of the protein.
- Boom! Bovine Spongiform Encephalopathy was born.
The Naming Story
How It Spreads
BSE spreads in a very unusual way:
Between cows:
From cows to humans:
Human to human:
- Contaminated neurosurgical instruments: Prions can cling to tools used in brain surgery and resist normal sterilization.
- Dura mater grafts: Transplants of the brain’s protective membrane from donors who unknowingly had a prion disease.
- Human-derived growth hormone injections: Back when growth hormone was taken from human pituitary glands, some batches carried prions.
- Certain transplant procedures: Very rare cases involving corneal or other tissue transplants from infected donors.
Modern hospitals now use:
- Prion-specific sterilization
- Strict donor screening
- Synthetic (not human-derived) growth hormone
- Better infection control protocols
Pet foods today?
Death Toll and Impact
The BSE crisis was no small ripple - it was a seismic shock:
- Over 180,000 cattle affected in the UK
- Approximately 230 human cases of variant CJD worldwide
- Billions lost in trade embargoes
- Massive culling of cattle herds
- Collapse of consumer trust
- Long-term changes to global livestock feeding and food-processing laws
Families were affected, farmers lost livelihoods, and entire nations tightened their safety nets.
Political and Social Atmosphere
The late 1980s and 1990s saw intense debate:
- Governments hesitated to alarm the public.
- Farmers feared economic ruin.
- Countries placed strict bans on British beef.
- Consumers felt betrayed and frightened.
Scientists begged for transparency while trying to calm a worried public.
It became a global case study in crisis communication and how fear can spread even faster than a pathogen.
Actions Taken
The response became one of the biggest food-safety overhauls in history:
- Bans on feeding animal-derived proteins to cattle
- Massive cattle culls
- Strict surveillance programs
- Removal of high-risk tissues from the human food chain
- Changes in rendering processes
- Mandatory traceability systems
- International regulations and export rules
Prevention for Pet Parents and the Public
A. What Pet Parents Can Do:
- Buy beef products from reputable sources
- Avoid feeding pets raw bovine nervous tissue (rare today, but still)
- Don’t source home-slaughter beef unless you know the animal’s history
- Follow official recalls and advisories
- Practice safe handling of raw meat
B. What Vets and Health Professionals Do:
- Monitor livestock health
- Report neurological signs in cattle immediately
- Implement strict testing and surveillance
- Guide farmers on safe feeding and sourcing practices
- Work with public health systems during suspected cases
Treatment and Prognosis
Here’s the hard part:
Diagnosis is done through:
- Clinical signs
- Brain tissue testing after death
- Specialized laboratory methods detecting prion proteins
Prognosis?
This is why prevention and surveillance are everything in this story.
Fun Tidbits
Your Turn
The goal here isn’t to make you swear off burgers, glare suspiciously at every cow grazing in a field, or assume your neighbour’s cattle are plotting a neurological coup.
- helped you understand why the world once panicked over beef,
- made you raise an eyebrow at the words “spongiform encephalopathy,”
- or prompted the whisper, “Wait… a protein caused all that?”
- Save this post so the lesson doesn’t fade like mist on a morning farm.
- Share it with a pet parent, a foodie, a vet student, or that one friend who loves cow memes but has no idea what actually happened in the 90s.
- And drop your questions or your wildest “I thought Mad Cow was a conspiracy theory” moments, in the comments.
And remember:
Check out the previous post - Bovine tuberculosis (Mycobacterium bovis)



