This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.
During the 2016-17 MSHMP year, we introduced a graph, PED Chart 3, in response to the recurring question of if farms that break with PED had repeating histories of infection. The horizontal axis is shown at the top and indicates the number of farms that have broken in the current MSHMP season. New farms are added throughout the year as they break. On the vertical axis we list each of these farms’ PED historical number of breaks in past seasons. Outbreaks are colored in blue, a darker tone indicates that a farm has had more than one outbreak within the year, and grey indicates a lack of historical data (Figure 1).
Key Points:
- The MSHMP PED Chart 3 shows the PED infection (break) history for all farms that break with PED during the current year
- The PED history chart varies at different points in the season
- This suggests that sites that break with PED are not constantly the same
By tracking the PED history of farms that experience outbreaks in a given year, we can visualize whether farms that break have consistently struggled with PED in the past. The PED history chart varies at different points in the season. For example, Figure 1A shows the complete PED outbreak history for the MSHMP 2023-2024 season until the end of the season June 30, 2024. We can see that Farm 1 (the first column to the left) had reported PED outbreaks in the 2020-21, 2022-23, and 2023-24 seasons (reflected in the blue). Figure 1B shows the first outbreak case of the 2024-2025 season, in a farm that had reported PED in the 2021-22, 2023-24, and 2024-25 seasons. The chart shows only one farm in the horizontal axis since no other farm had reported a PED outbreak in the 2024-25 season at that point.
Figure 2 shows the total number of PED breaks in the last five MSHMP seasons, and number of farm breaks in three consecutive years during each MSHMP season. The last three MSHMP seasons have shown a decrease in the total number of PED outbreaks and it is uncommon for farms to break three consecutive years.