Comparison of alternatives to passive surveillance to detect foot and mouth disease incursions in Victoria, Australia

- The time to detection of an FMD incursion into Australia was estimated by simulation modelling.
- The current passive surveillance system took a median 20 days to detect an incursion.
- Introduction of screening at saleyards did not decrease the time to detection.
- Introduction of bulk milk testing reduced the time to detection to 18 days.
- Farmer education to enhance passive surveillance reduced the time to detection to 15 days.

This study aimed to evaluate strategies to enhance the early detection of foot and mouth disease incursions in Australia. Two strategies were considered. First, improving the performance of the current passive surveillance system. Second, supplementing the current passive system with active surveillance strategies based on testing animals at saleyards or through bulk milk testing of dairy herds. Simulation modelling estimated the impact of producer education and awareness by either increasing the daily probability that a farmer will report the presence of diseased animals or by reducing the proportion of the herd showing clinical signs required to trigger a disease report. Both increasing the probability of reporting and reducing the proportion of animals showing clinical signs resulted in incremental decreases in the time to detection, the size and the duration of the outbreak. A gold standard system in which all producers reported the presence of disease once 10% of the herd showed clinical signs reduced the median time to detection of the outbreak from 20 to 15 days, the duration of the subsequent outbreak from 53 to 42 days and the number of infected farms from 46 to 32. Bulk milk testing reduced the median time to detection by two days and the number of infected farms by six but had no impact on the duration of the outbreak. Screening of animals at saleyards provided no improvement over the current passive surveillance system alone while having significant resource issues. It is concluded that the most effective way to achieve early detection of incursions of foot and mouth disease into Victoria, Australia is to invest in improving producer reporting.