Fig 1.
The three different data-informed surveillance methods are shown diagrammatically with an accompanying description of which types of information they are informed by. For each surveillance method, two magnifying glasses are shown on the epiunits that would have been selected by each surveillance method at a surveillance effort of 20% (2/10 epiunits). Epiunits with outbreaks on them in the diagram indicate epiunits with outbreaks with start dates in month t (i.e., ‘outbreak epiunits’). The circle in (b) indicates the search radius chosen at a surveillance effort of 20%. Note that ‘Network’ and ‘Outbreak’ information are dynamic and require consistent collection while ‘Epiunit Location’ information (the latitude and longitude of the centroid of the epiunit) is static and does not change over time. ‘Outbreak’ information is a record of the epiunit and start date of a particular outbreak. ‘Network’ information records the start and end epiunit of all cattle shipment events. Note that the ‘Network Connectivity’ surveillance method selects sites to survey without using the information in the outbreak dataset, but the outbreak dataset is used to assess whether the epiunits selected for surveillance by this method experienced an outbreak during the relevant time period (see the ‘Network Connectivity Method’ subsection of the ‘Surveillance Methods’ section for more details). Icons are from Microsoft Powerpoint and are free to use without royalty or copyright (https://support.microsoft.com/en-us/office/insert-icons-in-microsoft-365-e2459f17-3996-4795-996e-b9a13486fa79).
Fig 2.
Performance of Surveillance Methods Across Surveillance Effort Levels.
The points represent the average percent of outbreaks each surveillance method detected across all t + 1 months at each surveillance effort level (5-35%). The ribbons represent the variability across months (the interquartile range). The Network Proximity method is unable to survey over 30% of the epiunits for all of the two-month networks and so it is only plotted until the 30% surveillance effort level (as opposed to 35%).
Fig 3.
Month-by-Month Surveillance Method Performance.
The bars in each panel show the number of outbreaks detected by each surveillance method at each surveillance effort level (5%, 15% 30% respectively) at each t + 1 month. The black line shows the number of outbreaks reported in each t + 1 month. The t + 1 months are ordered by decreasing number of outbreaks, with the left-most month having the most outbreaks. Versions of these graphs that correspond to 10%, 20%, 25% and 35% surveillance effort levels are in the supplementary material (Fig F in S1 Text).
Fig 4.
Best Surveillance Method Each Month.
Each panel shows the percent of outbreaks detected by the data-informed surveillance method that detected the most outbreaks in each t + 1 month at each surveillance effort level. The bars indicate the percent of outbreaks detected by the best surveillance method and the horizontal black line indicates the percent of outbreaks detected by the Random surveillance method at that surveillance effort level. The coloured bars indicate the data-informed surveillance method that detected the most outbreaks at that surveillance effort level for that t + 1 month. The t + 1 months are ordered by declining number of outbreaks, with the left-most month having the most outbreaks. Versions of these graphs that correspond to 10%, 20%, 25% and 35% surveillance effort levels are in the supplementary material (Fig G in S1 Text).