Study On The Pathogenicity Of A Novel Duck Reoviru

The pathogenicity of a new type of duck reovirus infection in Jining area was studied,and the NDRV strong strain LDW strain was selected to study the pathology of young ducks.Sixty healthy 1-day-old ducks were divided into two groups on average.The experimental group was injected subcutaneously with 0.1m L NDRV venom(104.5TCID50/0.1m L),and the control group was inoculated subcutaneously with 0.1m L sterile phosphate buffer(PBS).In the challenge group,the symptoms were flexion,split,retardation,weight loss and death.Extensive lesions and yellow-white focal necrosis were seen in the liver and spleen.The liver,heart,spleen,bursa of Farsi,thymus and kidney were taken for pathological section observation,and the liver cells with different degrees of fatty degeneration and necrosis and spleen lymphocyte necrosis were observed in histopathology.In summary,NDRV can cause immune organ infection of ducklings,which can lead to death in severe cases.At the 3rd,6th,9th,12 th,and 15 th day(dpi)of infection,6 ducks were taken from each group,3 ducks were taken from each group and 3 ducks from each group.The heart,liver,spleen,kidney,brain,bursa of bursa and thymus were taken and fixed with 4% paraformaldehyde solution for histopathological examination.NDRV was detected by indirect ELISA.Purified NDRV virus isolates were coated with 96 Wells as antigen.The mass concentration of NDRV was 0.4mg/L,the serum dilution was 1:800,the serum action time was 30 min,the enzyme-conjugate secondary antibody action time was 1h,and the substrate action time was 30 min.Under this condition,60 serum samples were detected with 100% accuracy.The levels of IL-2 and IL-6 were measured,and the results showed that the levels of the two cytokines increased significantly at the onset of the disease,and the value of IL-2 was the highest at 6dpi,indicating that the virus infection caused the inflammatory response of the ducklings.Intravenous anticoagulant blood samples were collected on the 3rd,6th,9th,12 th,15th,12 th and 18 th days after the challenge,and the contents of alanine aminotransferase(ALT),aspartate aminotransferase(AST),urea(BREA),uric acid(UA),γ-glutamyl transferase(γ-GT),albumin(ALB)and total protein(TP)in serum were determined.Each index showed a trend of rising first and then falling.In this study,NDRV infection experiments were carried out to analyze NDRV infection in ducks,study the pathogenicity of NDRV,and focus on the histopathological changes,immune damage,and immunosuppression of the body after NDRV infection.The significance of this study is to clarify the pathogenic characteristics of NDRV strong strain(LDW)in ducklings.