Mad Cow Disease

Mad cow disease, commonly called, as Bovine Spongiform Encephalopathy (BSE), is a progressive neurological disorder in cattle. Since this condition occurs in cows, causing a sponge-like destruction in the brain, the term bovine spongiform encephalopathy (bovine meaning cow, spongiform meaning sponge-like appearance, enceph meaning brain, pathy meaning pathology or abnormality) is used. Till today, mad cow disease has killed thousands of cattle, especially in the United Kingdom.

Mad Cow Disease: Causes, Symptoms and Treatment

The exact cause of mad cow disease is not confirmed yet. However, the most accepted assumption is that a modified surface protein called prions are the causative agent for mad cow disease. Prions, in normal structure and form, are natural constituents of the body. After undergoing conformational changes, these prions cause mad cow disease. The term prions was coined by Stanley Prusiner, M.D., California, who discovered them as tiny protein molecules capable of causing various life-threatening diseases in animals and humans. The epidemic of mad cow disease in British cattle was a result of feeding protein supplements and infected cows to live cows.

The symptoms of mad cow disease are aggression, nervousness, abnormal gait, decreased milk production and lack of coordination. In a diseased cow, the proteins, especially in the brain and central nervous system, are converted into dysfunctional, misfolded prions. The portion of the brain and nervous system, where the prions are located becomes nonfunctional. In due course of time, the mad cow disease spreads to other areas of the brain, thus finally killing the affected cow. An affected animal usually dies within 2 weeks to 6 months.

Mad cow disease 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. Current researches are ongoing to detect mad cow disease at the early stages. Though there are some treatment options to manage the symptoms for mad cow disease, there is no cure. There is nothing significant that can be done to control the disease.

Mad Cow Disease in Humans

For mad cow disease, the phenomenon of 'species barrier' has no profound effect. Hence, it can spread to other animals species as well as humans. The disease in sheep which was identified about 300 years ago is called scrapie. Mad cow disease when contacted in humans is known as Creutzfeldt-Jakob disease (CJD), named after two doctors who identified the symptoms for the first time. CJD causes slow dementia among people in the age group, 50 - 70. Recently, a variant version of Creutzfeldt-Jakob disease, referred to as vCJD was observed, that affects young individuals.

In humans, the incubation period of mad cow disease may last for many decades, even 40 years. The symptoms of mad cow disease in humans include anxiety, insomnia, abnormal posture, memory loss, withdrawal, behavior disturbances, which later progresses to increased fatigue, dementia and finally death. Death usually occurs within a year after the onset of the symptoms. Till February 2009, more than 200 people have been killed due to human versions of mad cow disease.

Scientists are of the opinion that mad cow disease can be transmitted to individuals who consume the brain and spinal cord of the infected cows. It is to be noted that meat of diseased cattle is not safe to consume even after cooking, as the conformation of prions remain the same before and after cooking.