Experimental infection of calves with Argentinean strains of bovine herpesvirus type 4 belonging to different genotypes

Abstract

Bovine herpesvirus 4 (BoHV-4) is a gamma-herpesvirus which has been isolated from cattle with diverse clinical signs and from apparently healthy animals. Although its pathogenic role is still unknown, the virus has been consistently isolated from vaginal secretions from aborted cows. Phylogenetic analysis of Argentinean BoHV-4 feld isolates revealed the existence of three distinct groups. In this study the in vivo behaviour of Argentinean BoHV-4 isolates belonging to two diferent genotypes was analysed (10/154: genotype 1; 07/435: genotype 3) by experimental challenge of calves. Although both BoHV-4 isolates were able to replicate in their host afer nasal infection, severe clinical signs were not observed. It was demonstrated that isolate 10/154 replicates better in nasal epithelium whereas isolate 07/435 was consistently detected in ocular secretions. Low antibody titers were detected by virus neutralization and ELISA assays. Neutralizing antibody titers to isolate 07/435 were detected. However, no serological response was detected to the isolate 10/154 belonging to the American genotype. Overall, this information suggests that there are diferences in the pattern of in vivo behavior of these strains. Further studies are required to understand the immune response to the infections caused by this virus.