Bovine Spongiform Encephalopathy in our Blood Supply
The well-being of the blood supply has always been a vital component of human existence. It is common knowledge that the existing blood supply is deficient to the increasing usage of blood and blood products. Ironically, as the topic of blood donation arises in society, fears and doubts as to how sanitary and healthful the blood of blood donors often surface. For instance, there is much criticism over allowing foreign travelers to Great Britain the opportunity to donate their blood. This criticism stems from the belief that the Great Britain endemic of Bovine Spongiform Encephalopathy (BSE or “Mad Cow Disease”) can be physiologically related to the lethal Creutzfeldt-Jakob disease in humans. Although there is hardly any scientific evidence that supports this allegation, the United States Department of Agriculture and the FDA have introduced strict restrictions concerning the importation of British cattle products and the blood donation of British travelers. Critics, politicians, and the general public often utilize the conjecture of illegitimate facts and myths to shape their opinions concerning BSE. This is fine and great, but I believe a valid opinion on the subject must be backed by significant facts entailing the clinical epidemiology and history of Bovine Spongiform Encephalopathy, its relation to other transmissible spongiform encephalopathies (TSE), possible transmission to the human species, the causes of Creutzfeldt-Jakob disease, and any relationships between BSE and Creutzfeldt-Jakob disease. My opinion, based on the facts, is what I offer to you.
Bovine Spongiform Encephalopathy (BSE)
Bovine spongiform encephalopathy is a fatal brain disease of cattle. BSE is most common in dairy cattle, but not rare in beef cattle either. Cattle affected by BSE experience a progressive degeneration of the nervous system. Infected animals may show changes in behavior such as nervousness or aggression (hence the term “mad cow disease”), abnormal posture, lack of milk production, anorexia, and excessive licking. All cattle affected with BSE either naturally succumb or are euthanized. BSE is most often found in the Holstein-Fresian of cattle, although all breeds are suseptible. The disease usually is introduced to the cattle near puberty (12-15 months), and the incubation period of the disease is 5 or more years. The period of actual infection to death is frighteningly brief; the animal is usually dead within 4 months of showing symptoms.
BSE belongs to a group of animal diseases term Transmissible Spongiform Encephalopathy (TSE). Different forms of TSE diseases can affect felines, rodents, and other ruminant animals. The microorganism responsible for BSE and TSE’s is smaller than the smallest viruses. This microorganism is called a prion. Prions are exclusively host-coded proteins that attack the brain and nervous system of host animals, destroying brain tissue and dismembering the nervous system. The brains of affected animals take on a sponge-like texture, which explains the term “spongiform” in the clinical name. Prions do not trigger immune responses or inflammatory reactions, which is why they are unable to be detected until post-mortem (after death) examination of victim animals.
Mad Cow Disease most likely originated from feeding cattle bone and meal products of sheep infected with scrapie. Somehow, scrapie mutated to affect cattle, and BSE came to be. The first cases of BSE were discovered in Britain in 1985. Quickly, BSE raved havoc on the British dairy industry, killing over 176,000 cows within 10 years.
Impact of British BSE on US, and the Ban on Importing British Cattle
A majority of countries took a zero-tolerance approach toward British dairy products. Since BSE was such a big scare in Great Britain, nobody cared to bring the disease back to their countries. That is when the restrictions started. Since 1989, the USDA (United States Department of Agriculture) has prohibited the importation of live ruminants from BSE-affected countries. Ruminant products, such as fetal bovine serum, bonemeal, meat and bone, and offal were also prohibited from entry. Although “no cases of BSE were ever found in the U.S” (APHIS- United States of Agriculture), I believe the restrictions were a good idea. The best policy to prevent Bovine Spongiform Encephalopathy from entering the U.S. is to prevent bovines (live, and their tissue products) from entering.
Creutzfeldt-Jakob Disease and its relationship with BSE.
The fear of Cruetzfeldt-Jakob Disease influenced many officials to force the USDA to ban British cattle. Cruetzfeldt-Jakob Disease (CJD) is a degenerative brain disease found in humans. Symptoms-wise, it is similar to BSE, where increased aggression, degeneration of brain functions, and death are potential symptoms. However, according to the United Kingdom’s Spongiform Encephalopathy Advisory Committee (SEAC):
“With the 10 diagnosed cases of CJD on March 20, 1996, there was no direct scientific
evidence of a link between Bovine Spongiform Encephalopathy and Creutzfeldt-Jakob
to exposure to BSE were due to finding traces of a prion specified bovine offal (SBO).
This prion, however, would have been ineffective in finding evidence relating BSE and
CJD due to the USDA’s ban of SBO in 1989.”
After these foundings were published, 45 cases of CJD were identified. They still have yet to be found relative in any way to BSE.
Blood or No Blood?
With 10 diagnosed cases of CJD having a diminutive chance of being related to BSE, compared to the thousands of cattle infected with BSE in Great Britain, I’d say the USDA and FDA did a good job of preventing the spread of BSE to the U.S. The problem lay in keeping the cattle away, not in excluding the British from donating blood. I see no reason for the United States to continue to prohibit British travelers from donating blood. It has been proven over and over that BSE and CJD are similar in symptoms and origin, but share no direct relationship when transmission to humans is a factor. The risk of BSE to humans is almost nil, and the FDA is just being overly cautious with its bans. The blood of willing donors should not be excluded with such flimsy evidence; it is too costly to those who depend on the depleting remnants of the human blood supply.
United States Department of Agriculture/ APHIS, “Factsheet: Bovine Spongiform Encephalopathy.” September 1999. Website: http://www.aphis.usda.gov
University of Illinois-Urbana, “BSE- Bovine Spongiform Encephalopathy” Website: http://w3.aces.uiuc.edu/AnSci/BSE/
The Atlantic Monthly, “Could Mad-Cow Disease Happen Here?” Volume 98, Issue 9.
Mizutani, Hirotsugu Shiraki, “Clinicopathological Aspects of Cruetzfeldt-Jakob Disease.” Copyright 1985, Amsterdam, Netherlands.
Ensminger, M. E, “Animal Science.” Copyright 1991, Danville, IL.