Comparative histopathological study of rabbit haemorrhagic disease (RHD) and European brown hare syndrome (EBHS)

Histopathological lesions due to rabbit haemorrhagic disease (RHD) and European brown hare syndrome (EBHS) were studied in 35 rabbits and seven hares. Both rabbits (Oryctolagus cuniculus) and hares (Lepus europeus) regularly showed severe necrotizing hepatitis. In RHD, coagulation necrosis, mainly confined to the periphery of the lobules, was consistently found. In EBHS, lytic necrosis affecting the whole lobule was conspicuous, at least in severe cases. Particularly in EBHS, necrotic hepatocytes exhibited a special kind of karyorrhexis. In rabbits with a subacute or subclinical form of disease, early liver cirrhosis was observed. Depletion of lymphocytes was a regular feature in spleens of rabbits and was frequently found in hares. In RHD, disseminated intravascular coagulation (DIC) and haemorrhages in different organs, especially in kidneys and lungs were constant findings. DIC was never seen in EBHS and haemorrhages were an infrequent finding.