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

BMC Research Notes

Gerald AH Wells⁴  John W Wilesmith¹  Michael Dawson³  A Robin Sayers²  Marion M Simmons²  Michael J Stack³  Steve AC Hawkins²  Saira Cawthraw²  Anthony R Austin⁵  Mark E Arnold²  Timm Konold² 

[1] Barton, 1 Woodham Road, Woking, UK;Specialist Scientific Support Department, Animal Health and Veterinary Laboratories Agency Weybridge, New Haw, Addlestone, UK;TSE Department, Animal Health and Veterinary Laboratories Agency Weybridge, New Haw, Addlestone, UK;Formerly - Consultant Veterinary Pathologist, Veterinary Laboratories Agency, New Haw, Addlestone, Surrey, KT15 3NB, UK;Oak Farm, Harpsden Bottom, Henley-on-Thames, UK

关键词: Prion protein gene;    Risk of infection;    Model;    Incubation period;    Attack rate;    Dose–response;    Oral dose;    Cattle;    BSE;    Bovine spongiform encephalopathy;   

Others  :  1165050
DOI  :  10.1186/1756-0500-5-674

 received in 2012-06-12, accepted in 2012-11-27,  发布年份 2012

【 摘 要 】

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.

【 授权许可】

   
2012 Crown et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

Figure 2.

【 参考文献 】

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