Risk of BSE from the import of cattle from the United Kingdom into countries of the European Union.
This study assesses quantitatively the risk that other countries, in particular those within the European Union, have incurred by importing cattle from the UK during the period before or shortly after the ban on the import of live breeding stock was introduced in 1989. It does this by assessing the probability that animals imported from the UK in a certain year would have become a detected BSE case, had they not been exported. Using the annual incidence rates available for separate birth cohorts and a given culling rate, a cumulative incidence for each birth cohort was calculated. These figures were then combined with the numbers of live breeding cattle imported from the UK into the other countries of the EU, to give an import-related risk index for each country, assuming that their culling rates were similar to that in Great Britain. The countries could thus be categorised in terms of the number of cases of BSE they might have expected.