Pathobiology And Pathogenesis Of Chickens Infected With H5N1 Avain Influenza Virus

Avian Influenza as a typeâ… communicable disease that causes high fatality rate amongst humanand animals has always received public attentions. This study uses ultramicro-pathematologicalmethod study the pathology of a strain of H5N1 AIV from both cellular and deuto-cellular level.Observations are made on organs and tissues of the inoculated SPF chicken and theirlutramciro-pathematological changes documented, thus showing the pathology of this strain ofH5N1 AIV on inoculated chickens.Study has shown that major pathological changes appeared from day 1 to day 14 of inoculations.Most of the symptoms disappeared 21 days post inoculation. After inoculation, chicken showedbroad damage to major organs. The most seriously effected ones are the heart, lung, brain, kidneysand the immune system. Effects on digestive systems appeared less. Major pathological damageincludes myocardial cell necrosis, infiltration of inflammatory cell, parenchymatous myocarditis,pulmonary cell, blood vessel, and capillary wall sororities. Lymphocyte, macrophage, eosinophile,and granulocyte infiltration were also present. The pathological histology change mainly displayedparenchymatous myocarditis in the heart of the infecting chickens; interstitial pneumonia in the lung;hemorrhagic alterative inflammation in bursa of fabricius, thymus and cecal tonsil, nephritis inspleen; nonsuppurative encephalitis in cerebrum; acute renal glomerulus nephritis in kidney;alterative inflammation in liver and pancreas; acute catarrhal and hemorrhagic inflammation induodenum.The pathologies describled above causes widespread organ damages in a very shortperiod post inoculation and are the major contributors to the mass mortallity amongst the testsubjects, the ultramicro-pathematological changes to different extent in heart, lung, thymus, bursa offabricius, spleen, cerebrum, kidney and liver of the infected chickens. The changes containedvascular endothelial cell swollen and there were akaryocyte in lumens. Nucelus shrinkaged;heterochromatin concentrated or dissolved; bioblast swelled, even became vacuolization; roughendoplasmic reticulum distended; the integral cell dissolved in severity in parenchyma cell. Therewere virus-like particle in the blood vessel endothelial cells and parenchyma cells of the organs. Thisstudy also showed that 7-day chickens exibited much worse symptons than 21-day chickens. Theirsymptoms showed up earlier, lasted longer, and fatalities are also higher. 7-day chickens were alsomuch more suceptable to H5N1 infection. This demostrated there is strong correlation between thethe age which the test subjected is infected and the patholgies.