Antemortem diagnosis of rabbit haemorrhagic disease: a minimally invasive model for fulminant viral hepatitis

Abstract

Abstract Reliable antemortem diagnosis of rabbit haemorrhagic disease virus (RHDV) infection remains challenging, as confirmatory diagnosis still frequently relies on postmortem tissues. This observational proof-of-concept study evaluated a minimally invasive diagnostic workflow for in vivo hepatic sampling in rabbits clinically suspected of rabbit haemorrhagic disease (RHD). The approach integrates ultrasound-guided fine-needle aspiration cytology (FNAC), needle rinse cell block (NRCB) processing into paraffin-embedded cell tube blocks (CTBs), and immunohistochemical (IHC) detection of viral antigens. The procedure was performed under short inhalational anaesthesia with clinical monitoring. CTB sections displayed excellent cytological preservation and hepatic architecture, comparable to conventional postmortem liver sections. IHC revealed distinct and widespread cytoplasmic immunolabelling for RHDV antigens within CTBs, closely mirroring postmortem findings in all infected animals. No procedure-related complications were observed in control rabbits. These findings support FNAC-derived CTB/IHC as a feasible antemortem diagnostic approach for RHDV infection. Beyond its direct veterinary relevance, this approach may have One Health relevance within the framework of comparative hepatology and translational diagnostic method development, as naturally occurring animal diseases can provide useful models for evaluating diagnostic strategies in severe acute hepatopathies across species.