Animal diseases such as foot-and-mouth disease (FMD) and African swine fever (ASF) can have significant impacts on animal health, society, and the economy, especially in ‘free’ countries such as Australia. A disease such as FMD can not only spread in domestic cattle, sheep, goats and pigs, but also in feral populations, and between feral and domestic populations. It is challenging to form cost-effective Animal Health policy when diseases are rare or absent and there is uncertainty as to their arrival, spread mechanisms, and likely time to detection.
Epidemiological models can assist with the preparation of Animal Health policy by simulating outbreaks of disease at different locations and at different times of the year, in order to assess the effectiveness of potential control strategies and the level of resourcing that might be required for the response.
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The Australian Department of Agriculture, Fisheries and Forestry (DAFF) has supported the development of epidemiological models as decision support tools to support the formation of Animal Health policy. The regional-scale model AusSpread (Garner and Beckett, 2005), and its successor the national-scale model AADIS (Bradhurst et al., 2015), have helped inform complex policy questions such as the influence of resource shortfalls on disease control, potential benefits of emergency vaccination, early indicators on the potential extent of an outbreak, post-outbreak surveillance to support proof-of-freedom from disease, and the impact of post-outbreak management of vaccinated animals on return to trade.
Since its initial release in 2015, the AADIS model has evolved into a flexible modelling framework that can simulate contagious livestock disease, vector-borne livestock disease, transboundary animal disease, plant pests, environmental pests, and human disease. AADIS captures disease epidemiology, regional and seasonal variability in transmission (e.g., due to environmental differences and seasonal livestock production and marketing patterns), and multi-jurisdictional approaches to control. AADIS has a novel hybrid modelling approach that combines mathematical, agent-based, and cellular automata modelling techniques.