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