Author(s): Alexandrov M, Peshev R, Lasarova S, Doumanova L, Tchorbanov A
Liver and spleen obtained from rabbits deceased after inoculation with rabbit haemorrhagic disease virus (RHDV) were studied by means of light, transmission electron and immunoelectron microscopy. Severe damages located within the nuclei and cytoplasm of many periportal hepatocytes and splenic macrophages were detected. However, the most prominent pathological lesions were multifocal liver necroses abundantly infiltrated with heterophil granulocytes, as well as heterophils found throughout the red pulp of the spleen. Ultrastructurally, unique cell interactions were established. The cytoplasm of many hepatocytes/splenic macrophages was invaded with heterophils. Therefore, the term emperipolesis (penetration of heterophils toward the hepatocytes/splenic macrophages) was preferred for outlining these lesions. It was assessed that the observed emperipolesis may play a key role in the rabbit haemorrhagic disease pathology, as well as it could be the main reason for the development of smaller RHDV particles found by electron microscopy in the RHDV-positive specimens.