Mad cow disease is commonly known as Bovine Spongiform Encephalopathy (BSE). The term bovine spongiform encephalopathy is derived from the terms 'bovine', 'spongiform', 'enceph', and 'pathy'. The term bovine means cow, spongiform means sponge-like appearance, enceph means brain, and pathy means pathology or abnormality. It is a progressive neurological disorder in the cattle that is characterized by sponge-like destruction in the brain. Till today, BSE has killed thousands of cattle, especially in UK. Since BSE created a problem in UK, the US government laid rules to prevent the same. It has had only four cases of BSE in cattle.
The exact cause of BSE is not confirmed. Currently, the most accepted theory is that an abnormal version of a protein that is found on the cell surfaces called prions, is the causative agent for this condition. In the normal structure and form, prions are natural constituents of the body. However, due to unknown reasons, this protein alters and destroys the nervous system tissue (i.e., brain and spinal cord).
The term 'prions' was coined by Stanley Prusiner (M.D.) from California. He discovered them as tiny protein molecules, which are capable of causing various life-threatening illnesses in animals and humans. The epidemic of BSE in the British cattle, was a result of feeding protein supplements and infected cattle to the live cattle.
The symptoms of BSE include aggression, nervousness, abnormal gait, decreased milk production, and lack of coordination. The proteins in the brain and central nervous system of affected cattle are converted into dysfunctional and misfolded prions. The entire portion of the brain and nervous system where the prions are located becomes nonfunctional. In due course of time, the condition spreads to the other areas of the brain, eventually killing the cattle. An affected animal usually dies within 2 weeks to 6 months.
BSE is very difficult to diagnose in the early stages, as the incubation period can last for many years (2-8 years). Hence, diagnosis is possible only after the onset of notable symptoms. Though there are some treatment options to manage the symptoms, there is no cure. Currently, no significant steps can be taken to control the illness.
Creutzfeldt-Jakob disease (CJD)
For BSE, the phenomenon of 'species barrier' has no profound effect. Thus, it can spread to other animal species as well as humans. The illness that was identified about 300 years ago in sheep is called scrapie. While in humans, this illness is known as Creutzfeldt-Jakob disease (CJD). It is named after the two doctors who identified the symptoms for the first time. CJD causes slow dementia. Usually, the people affected by this condition fall in the age group of 50-70 years. Recently, a variant version of CJD (referred to as vCJD) was observed. This version affects young individuals. CJD may last for many decades, even 40 years. The symptoms include anxiety, insomnia, abnormal posture, memory loss, withdrawal, and behavior disturbances, which later progress to increased fatigue, dementia, and finally death. Death usually occurs within a year after the onset of the symptoms.
Scientists are of the opinion that BSE can be transmitted to individuals who consume the brain and spinal cord of the infected cattle. Thus, meat of diseased cattle is not safe to consume even after cooking, as heat does not affect the prions.
Disclaimer: This article is for informative purposes only and does not in any way attempt to replace the advice offered by an expert on the subject.