Canine Herpesvirus Latent Infection in Experimentally Infected Rabbits

Abstract

An experimental inoculation of canine Herpesvirus (HVC), strain H17, was performed in rabbits previously and simultaneously treated with dexamethasone, the behavior of the leukocyte count was followed prior and during the experimental phase. Upon death or euthanasia of the animals, a necropsy and evaluation of various organs was performed by histopathology and by nested PCR against the Herpesvirus Polymerase gene. All animals inoculated with dexamethasone showed leukopenia (p < 0.05), animals inoculated with HVC and treated with dexamethasone did not show significant histological lesions, but showed amplification of the Herpesvirus Polymerase gene in various organs despite not showing clinical signs of the illness. A dolphin Herpesvirus isolate was used as a positive control as rabbits developed fatal systemic disease and lesions typical of active (lytic) infection in various organs within 72 hours post-inoculation. The absence of clinical signs, significant histological lesions, and the presence of viral DNA in some organs suggested a state of latency due to canine Herpesvirus. Dexamethasone allowed HVC infection, but did not promote viral reactivation in rabbits contrary to that observed in canines experimentally induced to the lytic cycle by HVC.