[Spread of an intramuscularly administered live gE-negative BHV1 marker vaccine in 2 cattle farms].

Cattle are vaccinated with a live gE-negative BHV1-marker vaccine as a part of a programme to eradicate bovine herpes virus 1 in the Netherlands. To investigate whether this vaccine is transmitted to unvaccinated cattle in a herd after intramuscular administration, cattle from two herds were vaccinated: of a herd of 114 BHV1-antibody negative cattle on one farm, 45 animals were vaccinated, and of a dairy herd of 55 cattle in another farm, all 10 BHV1-positive animals were vaccinated. Vaccination was repeated after about a month. Antibodies against BHV1 were determined in all unvaccinated cattle to detect potential BHV1-antibody responses. Only one unvaccinated cow (from the dairy herd) showed BHV1 seroconversion. However, this antibody response was detected by a gE-ELISA as well as by a gB-ELISA. This indicates that the animal was infected by a field virus and not by the gE-negative vaccine virus. Thus intramuscularly administered live gE-negative BHV1 marker vaccine did not spread to unvaccinated cattle (n =154) on two farms.