A GE DELETED INFECTIOUS BOVINE-RHINOTRACHEITIS MARKER VACCINE FOR USEIN IMPROVED BOVINE HERPESVIRUS-1 CONTROL PROGRAMS

Based on a glycoprotein E (gE) deleted bovine herpesvirus 1 (BHV1) str ain (Kaashoek et al., 1994) a killed virus as well as a modified live virus marker vaccine have been developed that allow differentiation be tween immunized and BHV1 infected cattle. Safety and efficacy of both vaccines were tested extensively following the current European Union (EU) requirements for the development of bovine vaccines. The minimum vaccine dose, vaccination regimen, route of administration and duratio n of immunity were evaluated for both vaccines in comprehensive vaccin ation/challenge trials in cattle. The most potent adjuvant formulation for the killed virus vaccine was also selected by experimental challe nge infections. For the modified live virus marker vaccine it could be demonstrated that maternally derived BHV1 specific antibodies did not interfere with vaccination. Safety could be demonstrated for both the killed virus and the modified live virus vaccine in all target animal categories including veal calves, beef cattle, bulls, heifers and dai ry cattle, including pregnant animals.