Distinction between Aujeszky's disease virus-infected and vaccinated pigs by hemagglutination-inhibition test

Prevalence of antibodies of field pseudorabies virus in pigs of herd vaccinated with live vaccine

This trial was performed in a 350-sow farrow-to-finish pig farm in which animals had been vaccinated against Aujeszky's disease with glycoprotein gC deletion (gC(-)) vaccine. The prevalence of antibodies against field pseudorabies virus (PRV) in serum samples collected from sows and fattening pigs during the period March 1995 to May 1997 was determined by using a commercial assay kit. The frequencies with which PRV-positive sows were found were 28.9% and 25.0% in March and October of 1995, 12.5% and 2.5% in April and October of 1996, and 0% in May of 1997. The fattening pigs tested at these times had no antibody to field PRV. These results thus indicate the probability that the PRV infection at the farm was eliminated by the gC(-) vaccine.