Epidemiological models to support animal disease surveillance activities.

Epidemiological models have been used extensively as a tool in improving animal disease surveillance activities. A review of published papers identified three main groups of model applications: models for planning surveillance, models for evaluating the performance of surveillance systems and models for interpreting surveillance data as part of ongoing control or eradication programmes. Two Danish examples are outlined. The first illustrates how models were used in documenting country freedom from disease (trichinellosis) and the second demonstrates how models were of assistance in predicting the risk of future cases, detected and undetected, of a waning infection of bovine spongiform encephalopathy. Both studies were successful in advancing European policy changes to reduce the cost of surveillance to appropriate levels given the magnitude of the respective hazards.