Pathological Changes And Virus Distribution In Major Organ Tissues Of Specific Pathogen Free Chicks Infected With Infectious Bursal Disease Virus

21days old specific pathogen free chicks infected with IBDV. Use modern pathology andmolecular biology techniques combined with traditional pathology method to detect the numberand nucleus to cytoplasm ratio of plasma cells in lymphoid organ tissues, dynamic distribution ofIBDV in major organ tissues, pathology and morphology changes of tissues and cells. Relativequantitative method combined with the qualitative method to explore the relationship betweenvirus distribution and the pathomorphism changes of major organ tissues in IBDV infected chicks.This research aimed at comprehensively and systematically revealing the pathological injury andits possible mechanism in SPF chicks caused by IBDV. Provide scientific and experimental basisfor pathogenic mechanism exploring, clinical diagnosis, prevention and treatment of IBD. Thereaults showed that:1. Chicks infected with IBDV, the nucleus to cytoplasm ratio of plasma cells in thymus andbursa decreased (P <0.05or P <0.01) separately in3days and7-14days after virus infection;nucleus to cytoplasm ratio of plasma cells in spleen was less than the chicks in control group (P <0.05or P <0.01) in3-7days after virus infection; nucleus to cytoplasm ratio of plasma cells ingland of Harder was significantly increased (P <0.01) in the5th day; nucleus to cytoplasm ratio ofplasma cells in cecal tonsil decreased (P <0.05or P <0.05) in3-7days.2. Chicks infected with IBDV, the number of plasma cell in thymic medulla wassignificantly more than chicks in control group (P <0.01) in the3rd and7th day after IBDVinfection, plasma cell’s number in bursa Fabricius’ lymph nodule medulla decreased(P <0.05or P<0.01) in3-7days; number of plasma cell in spleen red marrow and manifolds of gland of Harderincreased significantly (P <0.01) separately in3-7days and5-14days; number of plasma cell ofcecal tonsil’s dispersion zone increased (P <0.01) in the3rd day and reduced (P <0.01) in the7thday after IBDV infection.3. IBDV can be detected with PCR technique in Major organ tissues. Virus was detected inthe1st to14th days in gland of Harder of chicks infected with IBDV. Gland of Harder was theorgan in which virus appeared earliest and existed longest; the second organ was bursa Fabricius in which IBDV was detected in2-14days after virus infection; cecal tonsil was the tissue in whichvirus existed shortest and was detected in2-5days after IBDV infection.4. Chicks infected with IBDV, bursa Fabricius’ pathology injury was the most serious, themajor performance was that bursa Fabricius swelled mildly in the beginning and atrophiedseriously later,color was dark yellow, texture was fragile, serosal surface had gelatin sampleexudate and sporadic hemorrhage spots, mucosal fold structure was chaotic and there was a lot ofmucus. Eye view lesions of the other organ tissues mainly displayed as acute inflammatory lesions,such as swelling, congestion and hemorrhage. Significantly pathological changes appeared in mostorgan tissues in3-7days after IBDV infection. The major performance showed that massivelymphocyte were necrosis or even disappeared, partial parenchyma cells became degeneration,necrosis and shedding, phagocytes and reticular cells proliferated. The pathological changesrecovered gradually in14-28days after IBDV infection, but there were still apparent inflammatorycells infiltration and hyperplasia of connective tissue.5. The ulstructure of lymphoid organ tissues changed significantly in3-7days after IBDVinfection in chicks. Mitochondrial cristae broked or even disappeared; Endoplasmic reticulumexpanded; high electron density particles appeared in the cytoplasm; intercellular space increasedand there were cell organelles and sporadic virus particles in it. In14-28days after IBDV infection,the ultrastructure changes restored gradually, but there were still a lot of fiber in intercellularspace.