Transmissible Spongiform Encephalopathies (TSEs), Including 'Mad Cow Disease': Public Health and Scientific Issues [Updated March, 1, 2004] [open pdf - 101KB]
"On December 23, 2003, the U.S. Secretary of Agriculture announced that a cow in Washington state had tested positive for bovine spongiform encephalopathy (BSE, or Mad Cow disease), representing the first domestic case. The Secretary announced expanded protections against BSE on December 30, 2003. On January 26, 2004, the U.S. Secretary of Health and Human Services announced additional safety measures for products regulated by the U.S. Food and Drug Administration (FDA) to protect public health. Both have stressed that the human health impact of finding one BSE positive cow is believed to be minimal. BSE is a member of a group of diseases called Transmissible Spongiform Encephalopathies (TSEs). Although the predominant theory is that TSEs are caused by prions or proteinaceous infectious particles (a novel disease mechanism first described in the 1980s), some scientists believe a virus may eventually be identified as the infectious agent. While some TSEs, such as scrapie in sheep, have been known for over 200 years, others, including BSE, appear to have emerged quite recently. Some TSEs seem to affect only one species and others, like BSE, appear to have jumped the "species barrier" to infect more than one species. This event has transformed prion diseases from a rare and esoteric area of research to a matter of significant public health concern. BSE is believed to have been transmitted to people who ate contaminated beef, leading to the identification in 1996 of a new human disease, variant Creutzfeld-Jakob disease (vCJD), in the United Kingdom."
CRS Report for Congress, RL32269
National Agricultural Law Center http://www.nationalaglawcenter.org/crs/