TSE infectivity model (TSEi) in animal tissues: Bovine intestines and mesenteries

Bovine Spongiform Encephalopathies, BSE, risk assessment, mathematical model, bovine intestines, mesentery tissues
First published in EFSA Supporting Publications
13 February 2014
Issued
7 February 2014
Type
External Scientific Report
Abstract

A stochastic quantitative risk assessment (QRA) has been developed to (1) compare the level of infectivity of different TSE agents in animal tissues, (2) estimate the impact of amendments to the list/age for the removal of SRM on residual TSE infectivity levels for a single infected animal and at the country level per year, and (3) estimate the impact of certain processing technologies on residual TSE infectivity in selected animal tissues or products. In this report the QRA is focused on bovine intestines and mesentery. The tissue types identified for quantitative modelling are: ileum, duodenum, jejunum, caecum, colon, mesenteric lymph nodes, mesenteric nerves and the celiac and mesenteric ganglion complex (CMGC). Of these tissues processed products include bovine intestines (duodenum, jejunum, caecum, and colon) used to produce sausage casings and the rendering of fats from mesentery tissues. The ileum is not processed for human consumption. This report describes the model approach taken together with the parameterization for each tissue type conceptually divided into five different components: surveillance, abattoir, SRM, processing, and infectivity. Both uncertainty and variability associated with input data have been included separately in the model where estimates are known. A baseline model has been completed using surveillance and demographic data from 2012. Two case studies are also provided, the retrospective analysis of the estimated amount of infectivity in the healthy slaughter and emergency slaughter streams by age at slaughter (2007-2011), and the amount of infectivity accumulating during a theoretical re-emergence of BSE. Results are provided based on the current parameterization and include associated quantifiable uncertainty and variability. When developing the risk assessment a number of assumptions were made which need to be considered when reviewing results.

Contact
biohaz [at] efsa.europa.eu
doi
10.2903/sp.efsa.2014.EN-559
Question Number
On request from
EFSA
Disclaimer
The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.