SHIC Reports Alarming Trends with Regards to PRRS Lineage 1C

Farmscape for July 19, 2023

Full Interview 12:37 Listen

The Swine Health Information Center reports an alarming counter seasonal regional increase in the number of PRRS detections.
As part of its monthly eNewsletter the Swine Health Information Center has released its domestic and global swine disease surveillance reports. SHIC Associate Director Dr. Megan Niederwerder says we saw a few concerning trends with regards to Porcine Reproductive and Respiratory Syndrome.

Quote-Dr. Megan Niederwerder-Swine Health Information Center:
Overall, we saw a reduction in the PRRS virus detection for positivity from May which was about 26.7 percent down in June to 23.1 percent but we saw some regional increases, specifically in Ohio. Then the data was analyzed in this previous month to look at the detection of the summer PRRS Lineage 1C variant detection. What was concerning about the Lineage 1C variant detection is that it had a trend of increasing the number of sequence detections during the summer. This is different than most other PRRS variants and it’s concerning with regards to that Lineage 1C variant for its characteristics and pathogenicity. Our advisory group suggested that there is a possibility that the PRRS Lineage 1C variant has longer shedding or perhaps a higher viral load in the animals. Also, there is a thought process that the Lineage 1C variant may have increased survivability with regard to environmental persistence. All of these characteristics may provide information, or at least hypothesis as to why the Lineage 1C variant has been different with regards to continued detection in summer months.

The Swine Health Information Center’s full domestic and global swine diseased surveillance reports can be accessed at

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