We're unable to sign you in at this time. Please try again in a few minutes.
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
Council Report |

Risk of Transmission of Bovine Spongiform Encephalopathy to Humans in the United States Report of the Council on Scientific Affairs

Litjen Tan, PhD; Michael A. Williams, MD; Mohamed Khaleem Khan, MD, PhD; Hunter C. Champion; Nancy H. Nielsen, MD, PhD; for the Council on Scientific Affairs, American Medical Association
JAMA. 1999;281(24):2330-2339. doi:10.1001/jama.281.24.2330.
Text Size: A A A
Published online

Context The risk of possible transmission of bovine spongiform encephalopathy (BSE) in the United States is a substantial public health concern.

Objective To systematically review the current scientific literature and discuss legislation and regulations that have been implemented to prevent the disease.

Methods Literature review using the MEDLINE, EMBASE, and Lexis/Nexis databases for 1975 through 1997 on the terms bovine spongiform encephalopathy, prion diseases, prions, and Creutzfeldt-Jakob syndrome. The Internet was used to identify regulatory actions and health surveillance.

Data Extraction MEDLINE, EMBASE, and Lexis/Nexis databases were searched from 1975 through 1997 for English-language articles that provided information on assessment of transmission risk.

Results Unique circumstances in the United Kingdom caused the emergence and propagation of BSE in cattle, including widespread use of meat and bonemeal cattle feed derived from scrapie-infected sheep and the adoption of a new type of processing that did not reduce the amount of infectious prions prior to feeding. Many of these circumstances do not exist in the United States. In the United Kingdom, new variant Creutzfeldt-Jakob disease probably resulted from the ingestion of BSE-contaminated processed beef. The United Kingdom and the European Union now have strong regulations in place to stop the spread of BSE. While BSE has not been observed in the United States, the US government has surveillance and response plans in effect.

Conclusions Current risk of transmission of BSE in the United States is minimal because (1) BSE has not been shown to exist in this country; (2) adequate regulations exist to prevent entry of foreign sources of BSE into the United States; (3) adequate regulations exist to prevent undetected cases of BSE from uncontrolled amplification within the US cattle population; and (4) adequate preventive guidelines exist to prevent high-risk bovine materials from contaminating products intended for human consumption.

Figures in this Article

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?


Figure 1. Schematic Representation of Conversion of Normal Prions to Abnormal Prions
Graphic Jump Location
Abnormal prion protein (PrPres) molecules (β-sheet isoform) become physically associated with normal prion protein (PrPsen) molecules (α-helix isoform) and induce a conformational change that converts PrPsen molecules to PrPres isoforms. The rate of conversion is influenced by the quality of the physical association between PrPsen and PrPres molecules. When accumulation of abnormal PrPres molecules is sufficient, clinical disease occurs. Abnormal PrPres molecules may originate from mutated human prion protein genes (inherited or sporadic), sporadic conformational abnormalities, or exogenous sources. If conformational differences between PrPsen and PrPres molecules prevent physical association of the isoforms, no conversion of PrPsen molecules occurs and clinical disease does not develop (lower panel).
Figure 2. Histopathology of Creutzfeldt-Jakob Disease and New Variant Creutzfeldt-Jakob Disease
Graphic Jump Location
Left, Typical spongiosis of the neuropil in the temporal cortex of a patient with Creutzfeldt-Jakob disease (hematoxylin-eosin, original magnification ×400). Photomicrograph courtesy of Carlos A. Pardo, MD, Johns Hopkins University School of Medicine, Baltimore, Md. Right, Cerebral cortex of a patient with new variant Creutzfeldt-Jakob disease containing 3 characteristic florid plaques with a dense core (arrowhead) surrounded by radiating fibrils and a halo of spongiform change (periodic acid–Schiff stain, original magnification ×120). Photomicrograph courtesy of James W. Ironside, National Creutzfeldt-Jakob Disease Surveillance Unit, Edinburgh, Scotland.



Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.


Some tools below are only available to our subscribers or users with an online account.

24 Citations

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

Related Content

Customize your page view by dragging & repositioning the boxes below.

Articles Related By Topic
Related Collections
PubMed Articles