AN INACTIVATED GE-NEGATIVE MARKER VACCINE AND AN EXPERIMENTAL GD-SUBUNIT VACCINE REDUCE THE INCIDENCE OF BOVINE HERPESVIRUS-1 INFECTIONS INTHE FIELD

An inactivated glycoprotein E-negative vaccine and an experimental gly coprotein D-subunit vaccine against bovine herpesvirus 1 (V1) were exa mined for their effectiveness in a randomized, double-bline, placebo-c ontrolled field trial comprising 130 dairy farms, The use of these mar ker vaccines enabled us to monitor the incidence of infections in vacc inated populations, The aims of this trial were to evaluate whether th ese vaccines, (1) reduce the proportion of outbreaks in daily herds; a nd (2) reduced virus transmission within dairy herds and to what exten t, Vaccination with either of the two vaccines significantly reduced t he proportion of herds wherein an outbreak occurred as well as the vir us transmission within herds, as compared to placebo-treated herds, Th e estimated number of secondary cases caused by one infectious animal expressed as the reproduction ratio R, was for both vaccines significa ntly >1. This indicates that when BHV1 is introduced into vaccinated h erds, major outbreaks may still occur. (C) 1997 Elsevier Science Ltd. All rights reserved.