INTENSIVE REGIONAL VACCINATION WITH A GI-DELETED VACCINE MARKEDLY REDUCES PSEUDORABIES VIRUS-INFECTIONS

The development of marker vaccines against pseudorabies virus (PRV) an d companion diagnostic tests have enabled us to perform a unique field trial. In this study, the effect of intensive regional vaccination on pig-finishing herd immunity was directly measured by comparing the se roprevalence of antibodies to glycoprotein I in trial and control grou ps. The seroprevalence of infected finishing herds in the trial region decreased from 81% at the start of the trial to 19% after 2 years (p< 0.001). The mean seroprevalence of infected pigs in these herds dimini shed from 49 to 5% (P<0.001). In the control group, representing routi ne PRV control, no significant change in seroprevalences was noticed.