NR ABUS
AU Brown,P.
TI Bovine spongiform encephalopathy and Creutzfeldt-Jakob- disease. The link is unproved, but no better explanation is presently forthcoming.
QU British Medical Journal 1996 Mar 30; 312(7034): 790-1
KZ BMJ. 1996 Mar 30;312(7034):791-3. PMID: 8608274 BMJ. 1996 Mar 30;312(7034):795. PMID: 8608277 BMJ. 1996 Mar 30;312(7034):843. PMID: 8608299
KI BMJ. 1996 Apr 20;312(7037):1037. PMID: 8616361 BMJ. 1996 Jul 20;313(7050):171-2. PMID: 8688797 BMJ. 1996 Mar 30;312(7034):791-3. PMID: 8608274
PT comment; editorial
VT
The identification of 10 cases of a highly stereotyped clinicopathological variant of Creutzfeldt-Jakob disease (CJD) in adolescents and young adults occurring in Britain within the past 24 months (R G Will, J Ironside, et al, personal communication) is cause for serious rethinking about the possibility of human infection from bovine spongiform encephalopathy (BSE).
Typically, "sporadic" (idiopathic) cases of Creutzfeldt-Jakob disease begin in the sixth or seventh decade of life with a loss of memory or, less commonly, with behavioural changes or higher cortical function deficits such as dysphasia or dyslexia. Over several weeks the mental deterioration progresses to frank dementia in association with abnormalities of vision or coordination, rigidity, and involuntary movements (especially myoclonic jerks), which often occur in synchrony with periodic spike waves on electroencephalography.[ii] Death usually occurs within six months, and at necropsy the brain shows a pathognomonic spongiosis with neuronal loss and gliosis in the cortex, deep nuclei, and cerebellum. Amyloid plaques are found in only about 5% of cases.[iii] Creutzfeldt-Jakob disease contracted from infected growth hormone also begins in a stereotyped way but with ataxia or other abnormalities of coordination.
By contrast, the newly reported variant syndrome is characterised clinically by onset with psychiatric symptoms and progressive neurological deficits with an unusual neuropathological profile (R G Will, I Ironside, et al, personal communication). This syndrome vividly recalls kuru, the epidemic spongiform encephalopathy in the eastern highlands of Papua New Guinea, which is thought to have been orally transmitted through the practice of ritual cannibalism, particularly the eating of brain tissue.[ii] All types of human and animal spongiform encephalopathy, including kuru, scrapie, and bovine spongiform encephalopathy, are experimentally transmissible in animals.
The ill defined early emotional and behavioural symptoms of the new variant will obviously open the floodgates to hundreds if not thousands of suspected cases of Creutzfeldt-Jakob disease over the next few years, and it will be a matter of enormous practical importance to be able to screen real from imagined cases. A soon to be reported spinal fluid test has shown itself to be both sensitive (97%) and specific (98%) for diagnosing the disease in even its early clinical stages and should prove extremely valuable in evaluating suspect cases (G Hsich, K Kenney, C I Gibbs Jr, et al, personal communication.)
Last November, the BMJ published a debate about the possibility of a link between bovine spongiform encephalopathy and Creutzfeldt-Jakob disease, to which I submitted a short article entitled "The jury is still out. "[iii] Despite this even handed title, I must confess to having felt that the available evidence favoured the idea that bovine spongiform encephalopathy constituted a negligible risk to humans. It now appears I was wrong. I am still astonished, in view of all of the earlier negative epidemiological and laboratory evidence concerning the risk of human infection from scrapie (the analogous disease in sheep), and from the failure to detect infectivity in the muscle of cattle with bovine spongiform encephalopathy, that human infection might be occurring from the ingestion of beef (or, even more improbably, from milk).
Especially distressing is the fact that no unusual dietary history characterises these cases - for example, the regular ingestion of calf brain, black puddings, sausage, or tripe because of the implication that a "normal" British diet has been sufficiently contaminated to have caused their infections. It is possible, of course, that these cases are not related to bovine spongiform encephalopathy, but it must be confessed that no better explanation is presently forthcoming. However, it must also be emphasised that the link to cattle products is itself only a presumption; how ironic, for example, if 11 million British cattle should be slaughtered m a preemptive strike to eliminate the risk of zoonotic Creutzfeldt-Jakob disease, only to find belatedly that the true villains were pigs or chickens which were also fed contaminated nutritional supplements but were brought to market at such a young age that the disease had not had time to become manifest.
A good deal of work remains to be done in order to establish the link between bovine spongiform encephalopathy and Creutzfeldt-Jakob disease, much of which has already been initiated. None of it will be of any help to those who may have been exposed to the infectious agent in the 1980s before precautionary measures were put in place to minimise the risk of human disease. Nor will it remedy the possible failure of the scientific pundits (including me) to foresee a potential medical catastrophe.
i. Brown P, Gibbs CJ Jr, Rodgers-Johnson P, Asher DM, Sulima MP, Bacote A, et al. - Human spongiform encephalopathy: the National Institutes of Health series of 300 cases of experimentally transmitted disease. Ann Neurol 1995;35:513-29.
ii. Gajdusek DC, Zigas V. Degenerative disease of the central nervous system in New Guinea. The endemic occurrence of kuru in the native population. - N Engl J Med 1957;257:974-8.
iii. Brown P. The jury is still out. BMJ 1995;311:1416.
ZR 3 Zitate
MH Animal; Cattle; Creutzfeldt-Jakob Syndrome/*transmission; Encephalopathy, Bovine Spongiform/*transmission; Food Contamination; Human
AD Paul Brown (pwb@codon.nih.gov), Medical director United States Public Health Service, Laboratory of Central Nervous System Studies, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
SP englisch
PO England
OR Prion-Krankheiten 2