A new report could give producers and veterinarians an early warning of potential swine health threats, improving preparedness and coordinated response across the industry.
Launched in August 2025, the new national surveillance effort enhances decision-making in swine health by identifying and communicating emerging porcine reproductive and respiratory syndrome virus (PRRSV) variants. Mariana Kikuti, recently appointed assistant professor at the University of Minnesota, is leading the development of the PRRSV Variants Under Monitoring (VUMs) Monthly Report in collaboration with the SHIC-funded Morrison Swine Health Monitoring Project and the PRRS-Loom analytical platform.
A machine-learning model, the PRRS-Loom tool, analyzes 603 ORF5 bases to classify viruses by lineage, sublineage and variants. These classifications, combined with a forecasting algorithm, anticipates whether a variant is likely to expand significantly, defined as more than a 20% increase in the next year, based on retrospective data with 77% accuracy, SHIC explains in the SHIC monthly newsletter.
“When integrated with the near real-time MSHMP data, the approach allows the new report to identify where specific PRRSV variants are already present and estimate their potential for wider spread,” SHIC explains.
What is a PRRSV variant?
PRRSV variants are defined as closely related viruses based on ORF5 gene similarity. These variants typically differ less than 2.5% within a variant and 5% from the nearest related variant. VUMs specifically represent PRRSV-2 variants circulating in the U.S. that show genetic and epidemiologic indicators of wider transmission, the article says.
To highlight urgency and guide responses, VUMs are categorized into four levels according to the number of sites impacted over the past six months:
Level 1 involves up to 30 sites
Level 2 involves 31–50 sites
Level 3 involves 51–100 sites
Level 4 involves >100 sites
For reports at Level 2 or higher, the VUMs will include expanded epidemiological discussion, examining affected sequences, sites, systems and states. SHIC says these summaries will be accompanied by epidemiological curves showing variant dynamics over time and situation reports that provide context for ongoing industry response.
“Together, these tools give stakeholders greater situational awareness, helping veterinarians and producers adjust strategies before a variant reaches wider distribution,” SHIC shares in the article.
Kikuti’s team is committed to making this information broadly accessible and focused on actionable information for producers. The VUM reports will be circulated to MSHMP participants, shared in SHIC’s monthly e-newsletter, and made publicly available on both the MSHMP website and the PRRS-Loom platform.
