Defines the number of recorded cases of Bovine SpongiformEncephalopathy (BSE) in the UK as comprising those reported to theMinistry of Agriculture, Fisheries and Food (MAFF) and…
Abstract
Defines the number of recorded cases of Bovine Spongiform Encephalopathy (BSE) in the UK as comprising those reported to the Ministry of Agriculture, Fisheries and Food (MAFF) and checked by them using histopathological techniques. Proposes that, if it is assumed that BSE is a similar condition to other mammalian transmissible spongiform encephalopathies (TSEs), and if other specific assumptions are made, it is possible to estimate the true number of cases of BSE and, hence, the number of human beings who have been infected in the UK. States that approximately 6.87 per cent of cattle born in 1988 became infected with BSE, with lower numbers in antecedent years, and that BSE cases reported in the UK represent approximately 23 per cent of the cattle which have become infected and are hence potentially infective to other animals, including man. Discloses the fact that TSEs of animals, of which BSE is one, can be transmitted to a mean of at least 70 per cent of other species and that oral transmission has been successful. Uses the potential levels of infectivity of the bovine products present in human food in the UK from 1984 to 1997, together with data as to individual diets within the population, to assess the number of people who would be expected to have eaten the minimum potentially infective dose or more. Discusses the possible effects on human health.
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Stephen Dealler, Nathaniel Rotowa and Richard Lacey
Three new microwave ovens that had been “approved” bythe Ministry of Agriculture, Fisheries and Food (MAFF) were each used toheat ten convenience meals. These meals were designed…
Abstract
Three new microwave ovens that had been “approved” by the Ministry of Agriculture, Fisheries and Food (MAFF) were each used to heat ten convenience meals. These meals were designed for microwave reheating and packet instructions were followed exactly. The foods were inoculated with 10⊃5−10⊃6/g of both S. typhimurium and L. monocytogenes, and core temperatures and bacterial numbers were measured before and after heating. Some viable listeria were still present in 97 per cent of the meals and viable salmonella in 80 per cent after heating. End core temperatures were much lower than expected with one food only reaching 43°C. The three types of microwave gave similar results. The reasons for these findings and their implications are discussed.
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A single case of a BSE infection was reported in June 2000 in a cow that had been born after the feed regulations were introduced in early August 1996 (born after the ban; a…
Abstract
A single case of a BSE infection was reported in June 2000 in a cow that had been born after the feed regulations were introduced in early August 1996 (born after the ban; a 1996‐BAB). This article is aimed at showing how, and when it can be claimed, that such cattle are either vertically infected (in which case they may be of lesser significance) or represent a further mode of disease transmission of BSE in the UK, in which case UK beef may remain undesirable to foreign markets. These calculations require the age at which BSE infection takes place in cattle to be known: this is demonstrated to be within the first seven months of life and generally within the first month. The possibility that BSE cases infected before the feed ban in 1996 were the result of an environmental source is considered. It is shown that, should this be so, the case number seen in the UK would become greater than that predicted for vertical transmission between December 2000 and May 2001 assuming that the proportion of cases that are reported remains as previously.
Philip Thomas and Martin Newby
Despite the small numbers of New‐Variant Creutzfeldt‐Jakob Disease (vCJD) observed, sufficient human data have now accrued to allow statistical estimation of all three of the…
Abstract
Despite the small numbers of New‐Variant Creutzfeldt‐Jakob Disease (vCJD) observed, sufficient human data have now accrued to allow statistical estimation of all three of the important parameters: the mean period between infection and death (the “mortality period”), its variance and the size of the outbreak. The mean mortality period is estimated to lie in the range six to 16 years, with low variances associated with the lower values of mean mortality period (< ten years) that are indicated as most likely. If BSE is indeed the cause of vCJD, then the number of human victims of vCJD is predicted not to exceed a few hundred, and is most likely to be a hundred or less. The study suggests that, while there may be a continuing, small number of deaths from vCJD for some years to come, exposure to the disease from BSE in the UK has more or less ceased at the time of writing.