Presence of bovine herpesvirus 1 gB-seropositive but gE-seronegative Dutchcattle with no apparent virus exposure

Two hundred and thirty-seven of 2052 cattle which had not been vaccinated a gainst bovine herpesvirus 1 (BHV-1) were seropositive in a glycoprotein B ( gB)-blocking ELISA, but seronegative in a glycoprotein E (gE)-blocking ELIS A. In order to detect whether they were latently infected with BHV-1, 10 of them were treated with corticosteroids in an attempt to reactivate putativ ely latent virus. After successive treatments with dexamethasone and predni solone, no virus excretion was detected and they showed no increase in anti body titres. In contrast, one gE-seropositive animal re-excreted BHV-1 and had a four-fold increase in antibody titre after the corticosteroid treatme nts. After slaughter, no BHV-1 DNA could be detected with a sensitive PCR i n samples of the trigeminal, cervical and sacral ganglia and spinal cords o f the gE-seronegative cattle.