Molecular, Clinical and Pathological Studies on Viral Rabbit Hemorrhagic Disease

Abstract

Rabbit hemorrhagic disease (RHD), is worldwide highly infectious disease of rabbits species Oryctolaguscuniculus. RHD is one of the major viral diseases which threaten rabbit population, caused by a calicivirus (genus Lagovirus). Multidisciplinary approach study on natural infection with rabbit hemorrhagic disease virus (RHDV) in foreign rabbit breeds from some provinces in Egypt was carried out. The postmortem and histopathology investigations in naturally infected rabbits showed hemorrhagic rhinitis with submucosal hemorrhages in trachea, bronchi and bronchioles. The lungs showed characteristic scattered hemorrhages, liver was congested friable with reticular pattern of necrosis. Focal hemorrhages were seen in kidneys and visceral organs. Bacteriological examination showed negative results of Pasteurella multocida isolation. Hemagglutination assay (HA) was performed on supernatants from liver homogenates resulted in similar positive hemagglutination by human O type and sheep blood. Reverse Transcriptase PCR was applied using specific primers for genomic region encoding the capsid protein VP60. The amplified cDNA was given size of approximately 540bp. Finally, our findings describe the pathological and molecular detection of RHD. Exclusion of pasteurellosis reinforced the results and hemagglutination assay with erythrocytes from mammalian and human O type was essential for identification of RHDV. RT-PCR proved to be confirmatory for the diagnosis of the RHDV.