University of Minnesota - “Serum Markers of PRRSV Infection”

Project Summary
Current, antibody-based diagnostics for PRRS are ineffective in the first, critical two weeks of infection before titers rise above the 0.4 S/P cut-off in the IDEXX PRRS HerdChek ELISA. They also are ineffective in differentiating acute from persistent infection and response to virulent infection from avirulent vaccination. The response of all animals, including pigs, to infection involves global mobilization of major organ systems to counter the pathogen and the damage it causes. These changes alter the composition of proteins in blood and serum and are specific for each disease agent, depending on sites of infection, affected cell and tissue types, and the characteristics of the agent. The researchers hypothesize that PRRSV infection will produce a characteristic profile of protein differences in serum that is a diagnostic signature of infection.

Project Objective
To determine the serum protein profile of PRRSV non-infected, acutely infected and persistently infected pigs.

Relevance to NPB PRRS Initiative Research Objectives
Monitoring PRRS infection in herds or individual pigs by presence of antibodies in serum misses the first critical 1-2 weeks of acute infection. Early detection would facilitate more rapid interventions to limit the spread of infection, thus improving herd health and productivity. Antibody-based diagnostics also provide minimal information on stage of infection, persistence, or viral virulence, and are not applicable to monitoring other conditions of health or disease. Identification of serum protein profiles that differentiate infected, vaccinated, naïve, and previously infected animals, as well as determine stage of infection, would have great value for monitoring the health of individual pigs and herds.