BSE, also known as mad cow disease, is a fatal prion disease affecting cattle that can be transmitted to humans. It was first identified in the UK in 1986 and over 180,000 cases were reported there between 1987-2007. The infectious agent is a misfolded prion protein that is not destroyed by cooking and can spread between individuals through contaminated food or animal feed. While there is no treatment or vaccine, prevention methods include banning cattle feed containing meat and bone meal and surveillance testing.
2. BOVINE SPONGIFORM
ENCEPHALOPATHY (BSE)
BSE is commonly known as mad cow disease. It is a progressive, fatal
prion disease of the nervous system and transmissible spongiform
encephalopathy in cattle that may be passed to humans who have eaten
infected flesh.
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3. HISTORY OF DISEASE
BSE was first recognized and defined in UK in November
1986.
From 1987 to 2007, UK has reported more than 180,000 cases
of BSE accounting for 97% of all cases reported throughout
the world.
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4. CAUSES OF DISEASE
The infectious agent in bovine spongiform encephalopathy is
a specific type of misfolded protein called a prion.
Prions can be transmitted to humans by eating food
contaminated with them.
Prions are not destroyed even if the beef or material
containing them is cooked or heat-treated.
Prion proteins carry the disease between individuals and
cause deterioration of the brain.
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5. TRANSMISSION
BSE is a transmissible disease that primarily affects the central
nervous system (brain & spinal tissue); it is a form of
transmissible spongiform encephalopathy, like
Creutzfeldt–Jakob disease in humans
Scrapie in sheep
Chronic wasting disease in corvids
The spread of this disease in cattle is caused by feeding
rendered material from infected cattle back to other cattle.
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6. SIGNS & SYMPTOMS
BSE has a long incubation period : 2-8 years.
Clinical signs of BSE are found in adult animals. Symptoms
may last for a period of two to six months before the animal
dies.
Animals with BSE may demonstrate some of the following
symptoms:
nervous or aggressive behaviour
Depression
hypersensitive to sound and touch, twitching, tremors
abnormal posture
lack of co-ordination and difficulty in rising from a lying position
weight loss
decreased milk production
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7. DIAGNOSIS
The BSE testing protocol calls for an initial rapid test called an
Enzyme-Linked Immunosorbent Assay (ELISA)
If the ELISA test is inconclusive, samples are sent for
confirmatory testing to the National Veterinary Services
Laboratories (NVSL)
An immunohistochemistry test Western Blot is conducted at
National Animal Disease Center (NADC)
The tests are designed to detect the presence of BSE-specific
abnormal prion protein in the brain tissue.
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8. VACCINATION/PREVENTION
No effective vaccine
A ban on feeding meat and bone meal to cattle from countries
where the disease was present
Surveillance measures
Blood/plasma donation restrictions
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9. TREATMENT
There is no treatment for BSE
Some of the symptoms can be managed
Treatment is palliative care
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