How many cases are we seeing of the new PRRS variant?

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.

As the MSHMP team continues to monitor the detection of the newly described PRRSv Lineage 1C RFLP 1-4-4 variant, they provide an update of the epidemiological curve of cases associated with this variant.

The updated epidemiological curve of the number of cases per week is shown in Figure 1. As of our last update, a total of 259 sequences from 14 MSHMP production systems have detected in 227 sites (84 growing pig farms, 57 breeding herds, and 86 with no information on site type). Coordinates were not available for 41% of cases. This strain continues to be detected in MN, IA, IL, SD and WI. The number of cases detected in this second transmission peak has already surpassed the number of cases in the first peak. However, although weekly number of cases seems to be decreasing, as new dataset comes in monthly a few weeks lag in identifying cases is expected. We will continue to monitor and communicate the situation.

Figure 1. Epidemiological curve of the PRRSv Lineage 1C RFLP 1-4-4 newly emerged variant.

It is important to highlight, however, that this analysis is based on sequence data obtained by the UMN, ISU, and SDSU Veterinary Diagnostic Laboratories of MSHMP participant systems and that non-MSHMP production systems may also be experiencing cases. Once again, we would like to thank the MSHMP participants for their willingness to share information. 

If you have any comments/suggestions on this topic or would like to raise a different topic to be investigated with the MSHMP data, do not hesitate to contact Cesar Corzo at and Mariana Kikuti at .

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