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ThesisItem Open Access PATHOMORPHOLOGICAL AND MOLECULAR DIAGNOSIS OF INFECTIOUS BURSAL DISEASE(College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati, 2020-12) ISLAM, MUZAHARUL; GOSWAMI, S.The present investigation was carried out to know the pathomorphology of Infectious Bursal Disease in different organized and un-organized poultry farms in and around the Guwahati city, Kamrup district, Assam. Altogether 1650 birds were necropsied, out of which 1279 birds from 29 different outbreaks were diagnosed as suspected of IBD based on gross lesions observed. Clinical signs commonly recorded were vent pecking, dullness, depression, anorexia, ruffled feathers and yellowish white diarrhea. In gross pathological study, bursa of Fabricius were found to be invariably affected with lesions like swelling, edema and hemorrhage. Few bursa of Fabricius showed atrophy. Moderate to severe haemorrhages in the breast and thigh muscle were consistently observed. The kidneys were enlarged and mottle with whitish pale colour appearance. Hemorrhagic lesions were also noticed in extra bursal lymphoid organs like spleen, thymus and caecal tonsils. Histopathologically, there were mild to severe depletion of lymphocytes in the bursa of Fabricius, spleen, thymus and caecal tonsils. Heterophilic infiltrations were also consistently observed in these organs. Complete depletion of lymphocytes with formation of cystic cavity were noticed in some bursal follicle. Marked thickening of the inter-follicular space with proliferated fibrous connective tissue were another characteristic bursal lesion observed. Muscle sections revealed haemorrhages and necrosis. Kidney showed degenerative changes and necrosis in proximal and distal convoluted tubules. There were glomerular shrinkage in few cases. Degenerative changes of the hepatocytes were the commonly observed histopathological changes in liver. In scanning electron microscopic study of bursa of Fabricius, moderate to severe erosion and ulceration of mucosal plica and exposure of reticular fibers were noticed after exuviations of epithelial and other cells were noticed. Button like depressed structures were seen in follicles and some follicles appeared as empty craters due to complete lymphocytic depletion. Spleen and thymus also showed moderate to severe lymphocyte depletion characterized by presence of homogenous mass. In transmission electron microscopic, spherical virus particle without a clear membrane were observed in the cellular debris of the cytoplasm of the follicular cells. Mitochondrial changes like crystolysis were also recorded. ABSTRACT The disease was confirmed by detection of viral antigen and viral nucleic acid in 165 representative samples by Indirect IPT and 612 representative samples by RT-PCR.ThesisItem Open Access PREVALENCE, PATHOLOGY AND MOLECULAR STUDIES OF PESTE DES PETITS RUMINANTS IN GOATS OF ASSAM(Assam Agricultural University, Khanapara, Guwahati, 2015-07) ISLAM, MUZAHARUL; Pathak, D. C.Peste des petits ruminants is an acute, febrile, emerging and economically important viral disease of goats having high morbidity and mortality rate. In the present investigation, 456 serum samples collected from affected and apparently healthy goats from different places of Assam were screened for seroprevalence of PPR in goats by HI test and c ELISA test. Out of 456 serum samples screened, PPR viral antibody could be detected in 269 samples by HI test (145 serum samples from affected goats and 124 from apparently healthy goats) and 209 samples by c ELISA test (136 from affected goats and 73 from apparently healthy goats). 60 serum samples (9 from affected goats and 51 from apparently healthy goats) showed positive in HI test but were found negative by c ELISA test. In comparative study it was revealed that HI test was more sensitive than c ELISA. The haematological study of 26 affected goats showed significant increase in total erythrocyte count, haemoglobin, packed cell volume and significant decrease in total leucocytes count. Lymphopenia was constant finding in differential leucocytes count. Biochemical study revealed significant decrease in serum protein and significant increase in serum potassium level, with nonsignificant increase of serum sodium level. All the 10 necropsied carcasses showed emaciation and dehydration with soiled hindquarters and sunken eye balls. Ulcerative lesions on gum, lips, dental pad and tongue, enteritis and linear haemorrhages on the crests of the folds of large intestine were invariably observed. The liver was enlarged with engorged gall bladder. Spleen and lymph nodes were enlarged. The lungs showed congestion and consolidation of anterior and cardiac lobes with emphysema in diaphragmatic lobes. On cut section, lung showed large quantities of white frothy exudate particularly in the bronchi. The histopathological study showed degeneration, necrosis, ulceration and sloughing off lining epithelium in lips, tongue, small intestine and large intestine. Below the ulcerated areas severe infiltration of mononuclear and polymorphonuclear cells were observed. Some cells of stratum granulosum showed presence of intracytoplasmic eosinophilic inclusion bodies. Hepatocytes showed coagulative necrosis with cytoplasmic and nuclear degeneration. The lungs showed broncho-interstitial pneumonia and presence of intracytoplasmic eosinophilic inclusion bodies. Renal tubular degeneration with coagulative necrosis and atrophy of glomeruli were observed. Edema in both the cortical and medullary areas with severe depletion lymphocytes was observed in the lymph node. Syncytial giant cells were also found in the lymph nodes. Spleen showed depletion of lymphoid population. Some lymphoid follicles were completely destroyed, leaving cystic cavities. In RT-PCR, out of 79 post mortem samples, 58 showed amplification of PPR viral nucleic acid at 463 bp for N gene using N gene specific primers.
