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| Curr Neurol Neurosci
Rep. 2002 Nov;2(6):488-95. |
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Bovine spongiform
encephalopathy, chronic wasting disease, scrapie, and the
threat to humans from prion disease epizootics.
Bosque PJ.
Division of Neurology, Denver Health Medical Center, 700
Delaware Street, M/C 4000, Denver, CO 80204-4507, USA.
patrick.bosque@dhha.org
Ongoing endemics and epidemics of prion disease afflict
several species of ruminants regularly consumed by humans.
Bovine spongiform encephalopathy (BSE) is epidemic in
British cattle, and is now found in the cattle of more than
20 countries. A large, and apparently growing, epidemic of
chronic wasting disease plagues deer and elk in North
America. Finally, scrapie has been endemic in the sheep of
most countries for many decades. It was once assumed that
humans were not susceptible to these ruminant forms of prion
disease, but an outbreak of a new form of Creutzfeldt-Jakob
disease (CJD) among young Britons, almost certainly due to
dietary exposure to BSE-contaminated beef, has disproved
this supposition. Although all prion diseases share the same
fundamental pathologic mechanism, transmission between
species is sometimes inefficient. The basis of this "species
barrier" is incompletely understood, but interspecies
differences in the amino acid sequence of the prion protein
and the strain of prions involved play critical roles.
Reliable experimental models for determining the resistance
of humans to animal prion diseases do not yet exist. It is
possible that animal to human transmission of prion disease
may manifest as CJD with unusual characteristics, but this
is not necessarily the case. In the absence of a reliable
means for determining the susceptibility of humans to animal
prion disease, measures to minimize human exposure to animal
prions should be emphasized.
PMID: 12359101 [PubMed - indexed for MEDLINE]
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