Subacute liver necrosis after experimental infection with rabbit haemorrhagic disease virus (RHDV)

Rabbit haemorrhagic disease (RHD) is usually peracute to acute, while subacute to chronic disease is rare. This paper describes gross and histopathological findings in four out of 20 rabbits aged 14 weeks, experimentally infected with one of two German field isolates of RHD virus. Eight rabbits survived the infection for 10 days and were killed after four of them, infected with 100 to 10 000 haemagglutination units, had started to develop progressive jaundice. Histopathologically, icteric livers showed severe subacute centrilobular bridging necrosis with calcification, and proliferation of periportal hepatocytes and bile ducts. Positive-strand RHDV RNA was detected by in-situ hybridization, mainly in periportal macrophages. Loss of the normal hepatic architecture, reparation (fibrosis) and hepatocellular regeneration, together with moderate inflammatory reaction, are signs of liver cirrhosis. These signs, observed in young rabbits given small doses of RHD virus, are interpreted as an unusual outcome of experimental inoculation.