didgood.com::Food & Health::Mad Cow/BSE

The exact cause of BSE is not known, but it is generally accepted by the scientific community that the likely cause is infectious forms of a type of protein, prions, normally found in animals cause BSE. In cattle with BSE, these abnormal prions initially occur in the small intestines and tonsils, and are found in central nervous tissues, such as the brain and spinal cord, and other tissues of infected animals experiencing later stages of the disease.

BSE in cattle was first reported in 1986 in the United Kingdom (UK). The exact origins of BSE remain uncertain, but it is thought that cattle initially may have become infected when fed feed contaminated with scrapie-infected sheep meat-and-bone meal (MBM). Scrapie is a prion disease in sheep similar to BSE in cattle. The scientific evidence suggests that the U.K. BSE outbreak in cattle then was expanded by feeding BSE-contaminated cattle protein (MBM) to calves. The definitive nature of the BSE agent is not completely known. The agent is thought to be a modified form of a protein, called a prion, which becomes infectious and accumulates in neural tissues causing a fatal, degenerative, neurological disease. These abnormal prions are resistant to common food disinfection treatments, such as heat, to reduce or eliminate their infectivity or presence. Research is ongoing to better understand TSE diseases and the nature of prion transmission.

BSE Map
Dates of First indigenous Cases
Source: OIE 2003

Cattle affected by BSE experience progressive degeneration of the nervous system. Changes in temperament (e.g., nervousness or aggression), abnormal posture, incoordination and difficulty in rising, decreased milk production, and/or loss of weight despite continued appetite are followed by death.

APHIS photos by Dr. Art Davis

Since 1989, USDA has banned imports of live ruminants, such as cattle, sheep and goats, and most products from these animals from countries known to have BSE. Subsequently, USDA expanded this ban to include both countries with BSE and countries at risk for BSE. In 1997, FDA prohibited, with some exceptions, the use of protein derived from mammalian tissues in animal feed intended for cows and other ruminants.

In cattle naturally infected with BSE, the BSE agent has been found in brain tissue, in the spinal cord, and in the retina of the eye. Additional experimental studies suggest that the BSE agent may also be present in the small intestine, tonsil, bone marrow, and dorsal root ganglia (lying along the vertebral column).

Vacuoles - microscopic holes in the grey matter - gives the brain of BSE-affected cows a spongelike appearance when tissue sections are examined in the lab.

APHIS photo by DR. Al Jenny

microscopic view of BSE-affected cow brain
Source: USDA:APHIS

The vast majority of cases of BSE (more than 97% as of 2003) have been reported from the United Kingdom during an epidemic. However, endemic cases have also been reported in other European countries including: the Republic of Ireland, Switzerland, France, Liechtenstein, Luxembourg, Netherlands, Portugal and Denmark. The numbers of reported cases by country are available on the web site of the Office International des Epizooties (www.oie.int/). These numbers should be interpreted with caution, however, because the intensity and methods of surveillance probably vary over time and by country. In 2003 one case was reported in Canada and one in the United States (in a cow born in Canada).

BSE Map
Geographical Distribution
Total Number of Cases on Indigenous and Imported
Source: OIE 2005

The status of known BSE cases in North America.

Offical Information

Getting BSE/vCJD

BSE Timelines

WebLinks

About.com

howstuffworks.com

Dmoz.org

Mark Purdey's An Explanation Of Mad Cow Disease Taken from Wise Traditions in Food, Farming and the Healing Arts, the quarterly magazine of the Weston A. Price Foundation, Spring 2002 The publishing website is a social arguement.[Editor's Note] This seems to be a duplicate of an earlier article.
http://www.ourcivilisation.com/madcow/index.htm

[Editor's NOTE] This story discusses how prions, CJD, BSE and how this sleeping disease are related.

Numbers

From the USDA's Animal and Plant Health Inspection Service

FAQs/Q & A

Rules & Regulation

Books, Images & Videos

Transcripts PBS:News Hour Is it Beef? MARCH 26, 1996
Margaret Warner interviews Dr. Will Hueston of the U.S. Department of Agriculture, he served on the advisory committee in Britain on looking into BSE, and Dr. Laura Maneulidis, head of the neuropathology section of the Yale School of Medicine.
http://www.pbs.org/newshour/bb/health/bse_3-26.html

Did Good

Mad Cow/BSE

Introduction