Mad cow disease – What causes Mad cow disease?
Mad cow disease is also known as Bovine Spongy form Encephalopathy (BSE). It attacks the Central Nervous System ( brain and spinal chord) of the adult cattle.
Causes of Mad cow Disease
It is caused by PRIONS (Proteinacious Infectious Particles) which are different from the known pathogens like viruses and bacteria. These are protein molecules. When normal body proteins change conformation( change their shape) they become pathogenic and are called PRIONS.
It is widely proposed that BSE originated from scrapie (endemic spongiform encephalopathy), a similar disease that infects sheep and goats. When carcasses of these sheep and goats were fed to cattle, the disease got transferred from goats and sheep to the cattle.
When humans consume the beef of an infected cattle the disease spreads to them. The disease in humans is called Creutzfeldt-Jakob disease. A variant form of CJD called variant CJD (VCJD) is believed to be caused by eating contaminated beef products from BSE-affected cattle.Till now, around 155 confirmed and probable cases of vCJD cases are noticed worldwide.
Symptom of Creutzfeldt-Jakob disease
The initial symptoms of Creutzfeldt-Jakob disease include the following:
- Lack of Muscular coordination
- Personality changes such as impaired memory, judgement, and thinking
- Impaired vision
- Unusual sensations
CJD does not cause a fever or other flu-like symptoms.
Advanced Symptoms of Creutzfeldt-Jakob Disease
Advanced symptoms of CJD include the following:
- severe mental impairment
- Myoclonus (involuntary muscle jerks )
- Inability to move and speak
At times, the patients of CJD die of pneumonia.
Is Creutzfeldt-Jakob Disease Transmissible?
CJD is not transmissible through normal social contact or through air. There is no specific risk to family members when compared to general population.
However there is evidence that suggests that CSF is transmitted through iatrogenic means such as transmsission during tissue grafting such as cornea transplantation, pituitary growth hormone implantation or through infected electrodes during Electroencephalograpy (EEG)
Research till now indicates that BSE is not transmitted through cow’s milk
FDA’s rule prohibits the use of cattle material that have the highest risk in harbouring BSE infection in human,such as gelatin.
The possibility that blood from people with vCJD may be infectious has led to a policy preventing people in the United States from donating blood if they have resided for more than 3 months in a country or countries where BSE is common.
Diagnosis of Creutzfeldt-Jakob Disease
No single diagnostic tool exists. Generally the diagnosis is carried out ruling other dementias with lesser complications.
- Spinal tap – (drawing and examining the cerebrospinal fluid) is the most commonly used method for diagnosis
- Computerized tomography
- Magnetic resonance imaging
- Brain biopsy – Removing the affected brain tissue slice by a surgeon and sending it for pathological examination. Highly risky procedure
- Autopsy- Examining the brain after the death of the patient
Treatment of Creutzfeldt-Jakob Disease
It is not curable. So the emphasis is more on alleviating the symptoms and increasing the comfort levels of patient.
- Opiate drugs help in reducing the pain
- Clonezepam Sodium valproate are used for treating myoclonus
Other Disease Management Measures
Other disease management measures include the following:
- Adjusting the postures in order to reduce the discomfort due to bedsores
- Catheters are used for draining out the urine
- Intravenous fluids are given. Artificial fluids are used at the advanced stages where feeding becomes difficult