Stability of porcine reproductive and respiratory syndrome virus and antibody in swine oral fluid

Materials and methods: A 4-L pool of swine oral fluid was collected from 16week-old finisher pigs. To ensure uniform, quantifiable levels of virus and antibody over time, 4 mL of PRRSV isolate ISU-P containing 1 × 1012 RNA copies per mL and 10 mL of concentrated hyperimmune anti-PRRSV antibodies were added to the pool. The pool was then divided into three equal portions: no treatment, chlorhexidine digluconate at 0.01% by volume, and isothiazolinone at 3 ppm. Each treatment was tested in triplicate at each of five temperatures (-20 ̊C, 4 ̊C, 10 ̊C, 20 ̊C, and 30 ̊C). Samples were removed at specific intervals (0, 12, 24, 48, 72, 144, 216, and 288 hours), stored at -80 ̊C, and then assayed for PRRSV RNA; IgM, IgA, and IgG PRRSV-specific antibody; and culturable bacteria per mL.