Bovine Spongiform Encephalopathy (BSE) also known as Mad Cow disease appeared in the mid 1980’s. This disease affects cattle. Affected cows show a variety of signs; anxiety, nervousness and initial hyperactivity only to become lethargic. This disease affects the part of the brain that controls gait, co-ordination and involuntary movement. These specific symptoms and signs led to the name, Mad Cow. Most cows affected were older dairy cows manly from the south of England.
It is believed that the cause of BSE in cattle was transmitted through cattle feed. BSE appeared after manufactures of cattle feed changed the way they prepared the feed that contained sheep carcass, consisting of brain, nervous tissue and other organs. It has been known for at lease 200 years that sheep have been affected by Ovine Spongiform Encephalopathy (OSE), also know as Scarpie. Just as with cattle, sheep affected with OSE act strangly. They continually bump into their surroundings causing loss of fleece and chunks of flesh.
Although it has not been confirmed that BSE or OSE are transmissible to humans, scientist believe that the similar disease that affects is no coincidence. Creutzfeldt - Jakob disease (CJD) a human Spongiform Encephalopathy is believed to have been transmitted through contaminated beef products. (Josephson, 1998)
Although this disease is rare it strikes 1 - 2 per million and unfortunately always fatal, usually within 1 year. Symptoms in humans range from depression, dementia and eventually loss of physical control of function, including inability to speak, muscle spasms, palsies and paralysis with vision distortions. Most affected are in their late 50’s. Incubation period can be 20 years or more. (Ratzan, 1998)
In all three disease OSE, BSE AND CJD are all called Spongiform Encephalopthy or SE because of the spongy like holes that are found in the brains of the affected. Scientist say that although there are good indications that SE is transmissible, they have not been able to identify a transmissible disease agent. (Josephson, 1998)
The fear that took the world by storm; TSE passing from sheep - to - cow - to - human, brought about many changes.
1. British order slaughter and incineration of over 37,000 head of cattle.
2. European countries banned the import of beef.
3. U.S. banned beef from Great Britain.
4. European Union banned orally ingestible medicines that contained animal by products.
5. FDA issued regulation instituting a mammal to ruminant feed ban.
(Josephson and Ratzan, 1998)