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. 2012 Dec 5:5:674.
doi: 10.1186/1756-0500-5-674.

Bovine spongiform encephalopathy: the effect of oral exposure dose on attack rate and incubation period in cattle - an update

Timm Konold  1 , Mark E Arnold, Anthony R Austin, Saira Cawthraw, Steve A C Hawkins, Michael J Stack, Marion M Simmons, A Robin Sayers, Michael Dawson, John W Wilesmith, Gerald A H Wells
Affiliations

Bovine spongiform encephalopathy: the effect of oral exposure dose on attack rate and incubation period in cattle - an update

Timm Konold et al. BMC Res Notes. .

Abstract

Background: To provide information on dose-response and aid in modelling the exposure dynamics of the BSE epidemic in the United Kingdom groups of cattle were exposed orally to a range of different doses of brainstem homogenate of known infectious titre from clinical cases of classical bovine spongiform encephalopathy (BSE). Interim data from this study was published in 2007. This communication documents additional BSE cases, which occurred subsequently, examines possible influence of the bovine prion protein gene on disease incidence and revises estimates of effective oral exposure.

Findings: Following interim published results, two further cattle, one dosed with 100 mg and culled at 127 months post exposure and the other dosed with 10 mg and culled at 110 months post exposure, developed BSE. Both had a similar pathological phenotype to previous cases. Based on attack rate and incubation period distribution according to dose, the dose estimate at which 50% of confirmed cases would be clinically affected was revised to 0.15 g of the brain homogenate used in the experiment, with a 95% confidence interval of 0.03-0.79 g. Neither the full open reading frame nor the promoter region of the prion protein gene of dosed cattle appeared to influence susceptibility to BSE, but this may be due to the sample size.

Conclusions: Oral exposure of cattle to a large range of doses of a BSE brainstem homogenate produced disease in all dose groups. The pathological presentation resembled natural disease. The attack rate and incubation period were dependent on the dose.

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Figures

Figure 1
Figure 1
Estimated probability of infection given the dose of brain homogenate used in the study. The probability of infection given the dose S(d) could be expressed as: S(d) = exp(−3.01+1.12*d)/(1+exp(−3.01+1.12*d)), which results in the updated graph displayed as continuous line. For comparison, the previous graph based on interim data is displayed as dotted line, as published in 2007 [1].
Figure 2
Figure 2
Estimated mean incubation period according to dose of brain homogenate used in the study. The updated graph displayed as continuous line is based on the current data. The previous graph based on interim data was published in 2007 [1] and is displayed as dotted line for comparison.
See this image and copyright information in PMC

References

    1. Wells GAH, Konold T, Arnold ME, Austin AR, Hawkins SAC, Stack M, Simmons MM, Lee YH, Gavier-Widén D, Dawson M, Wilesmith JW. Bovine spongiform encephalopathy: the effect of oral exposure dose on attack rate and incubation period in cattle. J Gen Virol. 2007;88:1363–1373. doi: 10.1099/vir.0.82421-0. - DOI - PubMed
    1. Wells GAH, Hawkins SAC. In: Techniques in prion research. Lehmann S, Grassi J, editor. Basel: Birkhäuser Verlag; 2004. Animal models of transmissible spongiform encephalopathies: Experimental infection, observation and tissue collection; pp. 37–71.
    1. Stack MJ. In: Techniques in prion research. Lehmann S, Grassi J, editor. Basel: Birkhäuser Verlag; 2004. Western immunoblotting techniques for the study of transmissible spongiform encephalopathies; pp. 97–116.
    1. Stack MJ, Moore SJ, Davis A, Webb PR, Bradshaw JM, Lee YH, Chaplin M, Focosi-Snyman R, Thurston L, Spencer YI, Hawkins SAC, Arnold ME, Simmons MM, Wells GAH. Bovine spongiform encephalopathy: investigation of phenotypic variation among passive surveillance cases. J Comp Pathol. 2011;144:277–288. doi: 10.1016/j.jcpa.2010.10.007. - DOI - PubMed
    1. Saunders GC, Griffiths PC, Cawthraw S, Tout AC, Wiener P, Woolliams JA, Williams JL, Windl O. Polymorphisms of the prion protein gene coding region in born-after-the-reinforced-ban (BARB) bovine spongiform encephalopathy cattle in Great Britain. J Gen Virol. 2007;88:1374–1378. doi: 10.1099/vir.0.82507-0. - DOI - PubMed

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