Article Text

PDF
A cohort study to examine maternally-associated risk factors for bovine spongiform encephalopathy
  1. J. W. Wilesmith, BVSc, MRCVS1,
  2. G. A. H. Wells, BVetMed, FRCPath, MRCVS2,
  3. J. B. M. Ryan, BEd, MIBiol, CIBiol1,
  4. D. Gavier-Widen, DVM, MSc, PhD2 and
  5. M. M. Simmons, BVMS, MVM, PhD, MRCVS2
  1. 1 Epidemiology Department
  2. 2 Pathology Department, Central Veterinary Laboratory, New Haw, Addlestone, Surrey KT15 3NB

Abstract

This long-term cohort study, initiated in July 1989, was designed to examine maternally-associated risk factors for bovine spongiform encephalopathy (BSE), forming part of the epidemiological research programme to assess the risks of non-feedborne transmission of BSE. In this study, the incidence of BSE in offspring of cows which developed clinical signs of BSE is compared with that in offspring, born in the same calving season and herd, of cows which had reached at least six years of age and had not developed BSE. All offspring were allowed to live to seven years of age. The results indicate a statistically significant risk difference between the two cohorts of 9.7 per cent and a relative risk of 3.2 for offspring of cows which developed clinical BSE. However, there is some evidence that this enhanced risk for offspring of BSE cases declined the later the offspring was born, but was increased the later the offspring was born in relation to the stage of the incubation period of the dam. The results presented cannot distinguish between a genetic component and true maternal transmission or a combination of both risks, but they do not indicate either that the BSE epidemic will be unduly prolonged or that the future incidence of BSE in Great Britain will increase significantly.

Statistics from Altmetric.com

Request permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.