BSE and transmission through blood

Abstract

Whether the outbreak of variant Creutzfeldt-Jakob disease (vCJD) in the UK will ultimately affect hundreds, or tens of thousands of people, cannot yet be predicted. 1 Ghani AC Ferguson NM Donnelly CA Anderson RM Predicted vCJD mortality in Great Britain. Nature. 2000; 406: 583-584 Crossref PubMed Scopus (179) Google Scholar If large numbers of apparently healthy people are now silently incubating infections with bovine spongiform encephalopathy (BSE), the implications for public health include the possiblity that blood from such individuals may be infectious. Established facts about infectivity in the blood of human beings and animals with transmissible spongiform encephalopathies (TSEs) are as follows: 2 Brown P Can Creutzfeldt-Jakob disease be transmitted by transfusion?. Curr Opin Hematol. 1995; 2: 472-477 Crossref PubMed Scopus (94) Google Scholar , 3 Brown P Cervenakova L McShane LM Barber P Rubenstein R Drohan WN Further studies of blood infectivity in an experimental model of transmissible spongiform encephalopathy, with an explanation of why blood components do not transmit Creutzfeldt-Jakob disease in humans. Transfusion. 1999; 39: 1169-1178 Crossref PubMed Scopus (267) Google Scholar , 4 Rohwer RG. Titer, distribution, and transmissibility of blood-borne TSE infectivity. Presented at Cambridge Healthtech Institute 6th Annual Meeting “Blood Product Safety: TSE, Perception versus Reality”, MacLean, VA, USA, Feb 13–15, 2000. Google Scholar •Blood, especially the buffy-coat component, from animals experimentally infected with scrapie or CJD and from either a clinical or preclinical incubation phase, is consistently infectious when bioassayed by intracerebral or intraperitoneal inoculation into the same species; •In naturally infected animals (sheep and goats with scrapie, mink with transmissible mink encephalopathy, and cows with BSE), all attempts to transmit disease through the inoculation of blood have failed; •Blood from four of 37 human beings with clinically evident sporadic CJD has been reported to transmit the disease after intracerebral inoculation into guineapigs, mice, or hamsters. But each success has been questioned on technical grounds and has not been reproducible; and •Epidemiological data have not revealed a single case of CJD that could be attributed to the administration of blood or blood products among patients with CJD, or among patients with haemophilia and other congenital clotting or immune deficiencies who receive repeated doses of plasma concentrates. Transmission of BSE by blood transfusion in sheepWe have shown that it is possible to transmit bovine spongiform encephalopathy (BSE) to a sheep by transfusion with whole blood taken from another sheep during the symptom.free phase of an experimental BSE infection. BSE and variant Creutzfeldt-Jakob disease (vCJD) in human beings are caused by the same infectious agent, and the sheep-BSE experimental model has a similar pathogenesis to that of human vCJD. Although UK blood transfusions are leucodepleted—a possible protective measure against any risk from blood transmission—this report suggests that blood donated by symptom—free vCJD-infected human beings may represent a risk of spread of vCJD infection among the human population of the UK. Full-Text PDF