Latent infection of cattle with bovid herpesvirus 2.

In a series of experiments, 10 calves were infected by different routes with bovine mammillitis strain of bovid herpesvirus 2 (BHV2). Nine of the calves developed lesions and BHV2 was isolated from 8 calves. At intervals, after clinical recovery, the calves were given a course of corticosteroid by intravenous injection. Subsequently 7 calves developed lesions and from 3 calves BHV2 was reisolated. The shortest interval between initial infection and reisolation of virus was 10 weeks. In one calf virus was recovered on 3 occasions, at intervals of 20, 44 and 74 weeks post-infection. It is probable that BHV2 can occur as a latent infection in calves and that BHV2 should be included among the herpesviruses known to remain latent.