Studies On The Pathology Of Geese Be Infected Artificial By Riemerella Anatipestifer And The Immunohistochemistry To Detect RA Antigen And Distribution Of RA Antigen In Infected Geese

Geese were artificially infected with Remerella anatipestifer serotype 1 at 21 days old to study the morphological pathology and to establish indirect immunohistochemistry methods to detect RA antigen and RA antigen distribution in infected geese. 30 hours post infected(PI) ,one goose was died and most of the others demonstrated clinical signs which were similar to that of duckings infected with RA; 46 to 72 hours PI, 50% of the goose showed highest mortality; 22 days PI20% of the geese survived. The gross pathological changes were as follows: fibrins on the seromembrane of all the organs, especially on the heart, liver, air sac and meningitis; swelling of liver and thymus ,swelling of spleen and bursal of Fabricius in early period and atrophy in the later stage, hyperemia and hemorrhage of the intestine, aberration of cecum in the later stage. Many parenchyma organs of infected geese showed fibrins and necrosis inflammation. Intestine showed hemorrhage inflammation. Few lymphocyte was found in spleen, thymus, bursa of fabricius and cecal tosil. Neutrophils infiltration could be seen in most of the organs.The best conditions for indirect immunochemistry were as follows: Fixing specimens with PLP, processing slides with APES, eliminating the activity of catalase and its similar enzyme with 0.3% formaldehyde-H2O2, blocking the tissue section with 10% albumin-tween-20 in humidity, restaining with toluidine blue. It was found that this method showed great specificity and sensitivity.The result of indirect immunochemistry demonstrated that: 24 hours PI, heart, liver, spleen, kidney, ileum, rectum, lung, duodenum and cecum were positive; 46 hours PI, all the organs showed positive results and some of the organs showed heterophile substances which could be stained by toluidine blue; 58 hours PI, the positive results were most obvious in all organs; 5 days PI, alveloar endothelial cells and hepatocytes showed positive in immunochemistry detection; 9 days PI, liver, kidney and thymus still showed strong results in immunohistochemistry detection while that of other organs began to decline; jejunum and pancreas showed less obvious results compared with other organs listed above in Immunohistochemistry detectionand brain was the least obvious.In summary, RA infection in geese could cause severe damages to parenchyma organs, intestines and the immune organs; pathological lesions were correlated with the distribution of RA antigen and neutrophils.