Experimental infection of New Zealand white rabbits (Oryctolagus cuniculi) with Leporid herpesvirus 4.

ABSTRACT

Leporid herpesvirus 4 (LHV4) is a novel alphaherpesvirus recently identified in domestic rabbits (Oryctolagus cuniculi). Little is known about the pathogenesis or time course of disease induced by this virus. We therefore intranasally inoculated 22 female New Zealand white rabbits with 8.4 × 10(4) CCID50 of a clinical viral isolate. Rabbits were monitored for clinical signs, viral shedding in oculonasal secretions, and development and persistence of serum antibodies. Rabbits were euthanized at 3, 5, 7, 14, and 22 d postinfection (dpi) to evaluate gross and microscopic changes. Clinical signs were apparent between 3 to 8 dpi, and included oculonasal discharge, respiratory distress, and reduced appetite, and viral shedding occurred between 2 and 8 dpi. Seroconversion was seen at 11 dpi and persisted to the end of the study (day 22). Severe necrohemorrhagic bronchopneumonia and marked pulmonary edema were noted by 5 dpi and were most severe at 7 dpi. Pulmonary changes largely resolved by 22 dpi. In addition, multifocal splenic necrosis was present at 5 dpi and progressed to submassive necrosis by 7 dpi. Eosinophilic herpesviral intranuclear inclusion bodies were detected in the nasal mucosa, skin, spleen, and lung between 3 to 14 dpi. LHV4 is a pathogen that should be considered for rabbits that present with acute respiratory disease. LHV4 infection can be diagnosed based on characteristic microscopic changes in the lungs and spleen and by virus isolation. Serum antibody levels may be used to monitor viral prevalence in colonies.