M03004: Transmissibility of BSE to pigs by oral exposure to brain homogenate
Wednesday 25 June 2003
This research project aims to determine whether BSE can be transmitted to pigs by including infected material in their feed.
Background
The UK pig herd have historically been exposed to BSE infectivity in the form of meat and bone meal from cattle. This study investigates whether transmissibility of BSE to pigs can occur by oral challenge of BSE-infected material.
Research Approach
Piglets were bred and fed only a ration free of meat and bone meal. After weaning at 7-8 weeks, challenge and control groups, each of ten piglets, were selected. The exposure dose was then calculated on the basis of replacing the theoretical maximum daily intake of meat and bone meal for the age of pig under commercial dietary conditions with an equivalent weight of brain tissue. Consequently, a pool of homogenised brains was prepared from confirmed BSE cases and 4kg of this, mixed with the normal ration, was fed to the challenge group on three occasions at 1-2 weekly intervals commencing at 8 weeks of age (May/June 1990). On each occasion, the pigs were observed to confirm that all had consumed the feed. Control pigs received only the normal ration.
Results and findings
Experimental oral exposure at eight weeks of age, with brain homogenate derived from natural cases of BSE, failed to produce evidence of the disease in pigs retained up to 7 years after exposure. No infectivity was found in a range of neural and non-neural tissues collected from these animals at 2 years after exposure or at termination.
Dissemination information
The final report will shortly be available from the FSA Library and Information centre. To obtain a copy, please contact the Enquiry Desk, Dr. Elsie Widdowson Library and Information Services, Food Standards Agency.
Tel: 020 7276 8181/8182 or email the library.
Contact: Stephen Dixon
Tel: 020 7276 8342
Email: stephen.dixon@foodstandards.gsi.gov.uk