Detection, Predictors, Immune Mechanisms and Prevalence of PRRSV Persistence in Boars.

Aimee Wasilk, Dr. Jane Christopher-Hennings

Abstract

Porcine Reproductive and Respiratory Syndrome (PRRS) is one of the most economically devastating disease in the swine industry. This syndrome affects pigs of all ages causing reproductive and respiratory symptoms. Polymerase chain reaction (PCR) based assays are commonly used to identify PRRSV carriers. In this study we will develop a real-time, quantitative PCR assay for the detection of PRRSV in porcine samples. Through this study we will determine the occurrence of boars that are persistently infected with PRRSV at 90 days after infection and if the virus hasn’t cleared, determine in which tissues the virus persists. We will also determine what immunological mechanisms are responsible for PRRSV persistence, by measuring cytokine concentrations including gamma interferon levels prior to PRRSV infection and weekly thereafter. The cytokines will be measured using quantitative PCR assays on serum and tissue samples. The gamma interferon levels will be tested using an ELISPOT assay.

The results from this study will help determine if viral clearance occurs and if immunologic responses can be correlated with limited PRRSV shedding. This will benefit swine producer and operators by enabling them to test, identify, and eliminate potential persistent PRRSV carriers from the herd.