Variant Creutzfeldt-Jakob disease vCJD

In human populations, exposure to the BSE agent (probably in contaminated bovine-based food products) has been strongly linked to the 1996 appearance of a new transmissible spongiform encephalopathy of humans called variant Creutzfeldt-Jakob Disease (vCJD). 

However, the emergence of variant Creutzfeldt-Jakob disease (vCJD) in the UK and France has raised concern about a new theoretical risk of infection in patients treated with blood and blood products (198). Animal experiments in which blood from sheep infected with bovine spongiform encephalopathy and natural scrapie-infected sheep into scrapie-free recipient animals have suggested disease transmission by the blood transfusion route in 2 of 24 sheep with bovine spongiform encephalopathy and in 4 of 21 sheep with scrapie (199). Many European countries have incorporated leukodepletion of all blood products, as leukocytes are believed to play a key role in the pathogenesis of variant Creutzfeldt-Jakob disease (198). In some countries, people who have lived in the UK for a period longer than 6 months between 1980 and 1996 are excluded from blood donation (13). Furthermore, it has been shown that various steps used in the manufacture of plasma-derived products also contribute to reduced infectivity by bovine spongiform encephalopathy (198). 

BSE is not transmissible to humans. However, there appears to be a strong connection between BSE and a variation of Creutzfeldt-Jakob disease, known as variant Creutzfeldt-Jakob disease (vCJD), another disease grouped with other TSEs. Evidence to date indicates that there has never been a case of vCJD transmission from person to person, but rather it is thought to spread from the consumption of cattle products contaminated with BSE. BSE and vCJD share many characteristics, to the point of being nearly indistinguishable from each other. Clinical studies have shown that mice inoculated with BSE showed the same pattern of incubation time, clinical signs, and brain lesions as mice inoculated with tissues from patients with vCJD. This provides evidence that BSE and vCJD are of the same strain . Furthermore, these two diseases were not similar to other TSEs such as sporadic CJD and known scrapies strains. 

Since the outbreak of bovine spongiform encephalopathy (BSE) in the United Kingdom in 1986 and its subsequent link to the human neurological disorder variant Creutzfeldt-Jakob disease (vCJD),... 

In other acquired prion diseases, notably scrapie of sheep and variant Creutzfeldt-Jakob disease (vCJD) in humans, amino acids encoded at certain key positions in the endogenous host prion protein are strongly associated with susceptibility to prion infection [57-59]. Studies of CWD in elk, mule deer, white-tailed deer, and moose have found that similar correlations between PrP amino acid sequence and likelihood of CWD infection could exist in these species as well. 

Of particular interest are prion amplification assays that are capable of detecting prions in blood components such as plasma. However, blood typically has extremely low prion concentrations (i.e., 13 LD50 per mL [59]), and contains inhibitors of some of the most sensitive tests such as PMCA [19] and another assay [60]. Recently, we integrated antibody 15B3-based immunoprecipitation with QuIC reactions to increase sensitivity and isolate prions from inhibitors such as those in plasma samples [61]. Moreover, replacement of the rPrPc substrate after 24h in RT-QuIC reactions substantially improved the speed and sensitivity of the assay. Coupling of the immunoprecipitation and substrate replacement steps, which we call enhanced QuIC (eQuIC), dramatically enhanced detection of variant Creutzfeldt-Jakob disease (vCJD) brain tissue diluted into human plasma. 1014-fold dilutions, containing 2 ag/ml of proteinase K-resistant prion protein, were readily... 

Prion diseases In the 1990s, four patients were infected with variant Creutzfeldt-Jakob disease (vCJD) after transfusions of non-leukodepleted blood. The incubation periods in the recipients were 6.5-8.3 years after transfusion. Leukocytes are now removed from blood used for transfusion [60, 96, 9T]. Plasma products carry a low risk of transmission of transmissible spongiform encephalopathies because of production processes [96 ]. The estimated risk depends on the prion load. Of plasma products, vCJD-implicated batches of clotting factor concentrates were categorized as likely to transmit prion diseases [9T]. In the UK, and before the exclusion of the use of British plasma, the risk of prion transmission by blood was estimated to be 7-14 per 10000 patients with hemophilia, assuming a vCJD population prevalence of 1 in 10000... 

Prions The use of bovine thrombin in fibrin sealants increases the risk of transmission of bovine spongiform encephalitis (BSE) [11 ]. However, the risk of transmitting prion diseases by giving human blood or blood products is theoretical at present. Because of the long incubation time it is challenging to evaluate the risk [2 ]. In 168 UK cases of variant Creutzfeldt-Jakob disease (vCJD), nine patients had received fractionated plasma products on 12 occasions, intramuscular immunoglobulins for travel on four occasions Rh(D) immunoglobulin for rhesus... 

Some specifically avoid beef because of the potential risk of contracting variant Creutzfeldt—Jakob disease (vCJD) from eating meat infected with bovine spongiform encephalitis (BSE). 

The human form of the disease is called Creutzfeldt-Jakob disease (CJD), which is rare and apparently arises spontaneously. The average age of onset of CJD is 64. In 1994, howeva-, several cases of the disease appeared in young adults in the U.K. To date, 200 cases have been reported. This new variant Creutzfeldt-Jakob disease (vCJD) is caused by ingesting meat products of an animal infected with the disease. 

Because they are derived from cattle, there is a concern that gelatins might be vehicles for the transmission of the prion agent responsible for bovine spongiform encephalopathy (BSE) in cattle and variant Creutzfeldt-Jakob disease (vGD) in humans. There is at present no evidence that these products have contributed to the transmission of BSE or vCJD. However, the incubation period may be up to several years, and due prudence is warranted when such products are used. 

Lucker, E., Horlacher, S., and Eigenbrodt, E. 2001. Brain in human nutrition and variant Creutzfeldt—Jakob disease risk (vCJD) Detection of brain in retail liver sausages using cholesterol and neuron specific enolase. Br. ]. Nutr. 86, S115-S119. 

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