A STUDY OF SOME BIOLOGIC PROPERTIES OF BOVID-HERPESVIRUS-4

This article summarizes the results of a study on several strains of Bovid herpesvirus-4 (BHV-4), isolated from cattle. The study had several objectives, namely, to verify (a) the disease-causing potential of the virus, (b) the possibility by BHV-4 to induce a latent infection in the natural host and (c) the entity of the relationships among strains of the virus isolated from different disease syndromes. The following data were obtained: (1) All strains tested were able to replicate in experimentally infected calves; however, only one strain (85/BH 16TV) caused an overt systemic disease. (2) The nervous system as well as the lymphoid structures appeared to be the target organs for replication of the virus. (3) BHV-4, like other herpesviruses, was able to establish latent infection in cattle. (4) When two strains of the virus, isolated from cattle affected by different disease syndromes, i.e. respiratory disease (strain DN-599) or vulvovaginitis (strain 85/BH 16TV), respectively, they resulted to be closely related to each other. In particular, they revealed a similar DNA pattern and both strains were able to cause respiratory disease in calves. Moreover, the two viral strains were mutually protective in that calves were generally found to be refractory to challenge inoculation with either the homologous or the heterologous virus. (5) All BHV-4 strains tested generally failed to evoke a significant production of neutralizing antibody in the experimental calves.