PRRS prevalence comparison among different MSHMP cohorts

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.

MSHMP Researchers Mariana Kikuti, Xiaomei Yue, Marcello Melini, Emily Geary, and Cesar Corzo break down PRRS prevalence among two cohorts of participating farms in this week’s Science Page.

Key Points

  • PRRS prevalence dynamics among cohorts remain relatively comparable.
  • Systems that joined the program later seem to have a higher prevalence of status 2fvi farms, particularly in the most recent years.
Figure 1. Prevalence chart of the farms of the systems that started the Project (CS), the ones that joined later (CL) and both cohorts combined. PRRS Status 4, 3, 2, 2vx, 2fvi, and 1 are represented in light green, green, beige, orange, red, and dark red, respectively.

The Morrison Swine Health Monitoring Project (MSHMP) originally started with 13 production systems who voluntarily shared their sow herd PRRSV disease status on a weekly basis. As the program continued to expand, the number of sow herds located in different regions provided a better perspective of disease occurrence dynamics. 

A comparison from a prevalence standpoint between the cohort of farms belonging to the original 13 systems at the start (CS) of the MSHMP and the cohort of farms from systems that joined the program later (CL) was performed with the objective of assessing how the patterns between cohorts compare. Although the historical prevalence of PRRS statuses according to the AASV categories are relatively comparable (Figure 1), the CS cohort have a higher prevalence of status 2vx herds while the CL cohort have a higher prevalence of status 2fvi herds in more recent years. 

Currently (in July 05, 2023), the proportion of farms using LVI in the CS versus the CL cohort is 2.2% and 12.9%, respectively (Table 1). 

The continuous addition of systems from multiple different regions to the program aims at increasing its representativeness and robustness to monitor swine diseases of importance to the U.S. industry.

Table 1. Percentage of farms in each AASV definition category for each cohort at current point in time (July). CS – cohort of systems that were present since the beginning of the project. CL – cohort of systems that have joined the Morrison Swine Health Monitoring Project after the CS.

Leave a Reply