Submitted to: Swine Research Report
Publication Type: Other
Publication Acceptance Date: 12/18/1998
Publication Date: N/A
Technical Abstract: Forty-eight pigs from a Porcine Reproductive Respiratory Syndrome virus (PRRS) naive (noninfected, nonvaccinated) herd were weaned, placed in isolation chambers, and oral-nasally inoculated with 2 ml of 10**4 JA142 PRRS virus particles. Pig weight, feed intake, and serum concentration of PRRS virus titers, gamma-interferon (gamma-IFN), and alpha-1-glycoprotein (AGP) were determined every four days for 24 days postinoculation. Serum virus titers and gamma-IFN, both peaked at four days postinoculation, and then declined steadily throughout the 24-day study. As expected, serum AGP responses were delayed with peak concentrations occurring 12 days postinoculation. Body weight gains and fee intakes of individual pigs were quantitatively related to the animal's serum concentration of virus titers and to a lesser degree serum concentration of gamma-IFN and AGP. Specifically, each additional log of serum virus titer was associated with .910 kg reduction in 4-day pig gain and a 1.127 kg reduction in 4-day pig feed consumption. These data support the hypothesis that serum concentration of virus is directly related to the magnitude of biological responses of the pig that occur in pigs infected with PRRS.