Reduction of the prevalence of pseudorabies virus-infected breeding pigs by use of intensive regional vaccination

The influence of an intensive vaccination program on prevalence of pseudorabies virus (PRV)-infected breeding pigs was examined in a region where the disease was enzootic. In a 2-year period, significantly (P < 0.005) greater decrease in the prevalence of PRV-infected breeding pigs was observed in herds participating in the regional vaccination program and in herds outside the trial region that intensified PRV vaccination during the study than in herds that applied routine PRV control measures. In the regional vaccination program, introduction of breeding stock from outside the area was significantly (P < 0.05) associated with higher prevalence of PRV-infected pigs at the end of the study. These results indicate that transmission of PRV can be markedly reduced by use of an accurately applied intensive vaccination program.