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20162
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Subject: Veterinary Pathology × End date: 2017 × Start date: 2015 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    PREVALENCE, PATHOLOGY AND MOLECULAR DIAGNOSIS OF POX IN DOMESTIC BIRDS
    (AAU, 2016) Pathak, Nayanjyoti; Baruah, G.K.
    In the present investigation a total of 29 nos. of fowlpox (FP), 13 nos. of pigeonpox (PP) and three nos. of duckpox (DP) outbreaks were recorded, where highest morbidity and cause specific mortality in case of FP was recorded at 0-8 weeks (19.63 % & 23.60 %) followed by 9-20 weeks (5.57 % & 14.43 %) and above 20 weeks (1.39 % & 11.11 %), respectively. Likewise, in PP highest morbidity was recorded at above 20 weeks (35.08 %) followed by 9-20 weeks (30.68 %) and 0-8 weeks (11.11 %). Highest cause specific mortality was recorded at 9-20 weeks (37.03 %) followed by above 20 weeks (30.00 %) and no mortality was recorded at 0-8 weeks. In case of DP outbreaks, highest morbidity was recorded at 0-8 weeks (10.00 %) followed by above 20 weeks (6.66 %), where no mortality was recorded among the ducks. During sero-surveillance study of FP, 27.88 % positive cases were detected by AGID, whereas 77.88 % positive cases were detected by ELISA. Similarly in case of pigeonpox and duckpox 26.82 % and 26.41 % positive cases were detected by ELISA, respectively but no positive cases were detected by AGID. Gross lesions during external examination revealed erosions, crusts and several small, multifocal to coalescing wart-like nodules on various parts of the affected fowls and pigeons, whereas in case of ducks lesions were mostly confined to bill and eye regions. During post-mortem examination of dead birds no any remarkable gross lesions were seen in various visceral organs where in few birds showed fibronecrotic lesions on mucous membrane of the oral cavity and upper respiratory tract. Microscopic lesions revealed varying degrees of hyperplasia and ballooning degeneration of the epithelial cells of the epidermis where most of the cells contained large eosinophilic intracytoplasmic inclusion bodies. During ultrastructural study, intracytoplasmic inclusion bodies were seen in the skin epithelium, which consist of numerous, dumbbell-shaped bodies typical of pox virions. During molecular diagnosis, out of 29 FP, nine PP and three DP suspected samples 86.20 %, 77.77 % and 100 %, respectively were found positive by polymerase chain reaction. Inoculation of fowlpox virus (FPV) in embryonated chicken eggs and inoculation of duckpox virus (DPV) in embryonated duck eggs for isolation showed positive results during the first passage itself , where as pigeonpox and duckpox viruses in embryonated chicken eggs required 2-3 initial passages to get the positive results. Out of the various field isolates, 10 nos. of FPV and six nos. of pigeonpox virus (PPV) were adapted on chorioallantoic membrane (CAM) of developing embryonated chicken eggs, whereas the virus isolated from ducks (n=3) were adapted on CAM of embryonated duck eggs. All total eight nos. of APV isolates were molecular biologically characterized. On phylogenetic analysis it was observed that all the isolates of APV of the present study were clustered along with other APVs corresponding to their species reported from different parts of the world. However, one isolate from duck was clustered along with the isolates of FP, which indicates natural adaptation of FPV in ducks. From the experimental study it was observed that all the chicks inoculated with FPV developed characteristic pox lesions (pustules) within 7-9 days post infection. Similarly, when pigeons were inoculated with PPV then all the pigeons developed pox lesions within 5-9 days. Again in case of ducklings all the ducklings inoculated with DPV developed pox lesions (nodular lesion) within 5-6 days. For comparative study when FPV, PPV and DPV were inoculated into heterologous hosts no lesions were developed. In seroconversion study of experimental birds by ELISA, all the infected birds (chicks, pigeons and ducklings) inoculated with species specific avipox virus showed presence of antibody. Antibody was also detected in 40 % pigeons and 60 % ducklings inoculated with FPV, 60 % chicks inoculated with PPV and 40 % chicks inoculated with DPV. The scab samples of experimentally infected chicks, pigeons and ducklings showed positive results by PCR but the biopsy samples collected from the inoculated site of the heterologous hosts showed negative results by PCR. Haematological studies in case of avipox infected fowl, pigeon and ducks from both field and experiment cases revealed low levels of haemoglobin, total erythrocyte count and total leucocyte count. In differential leucocyte count, lymphocyte and monocyte percentages were increased, whereas heterophil percentage was decreased in pox infected birds. From the experimental study it could be concluded that though the FPV, PPV and DPV field isolates of this study were host specific but if several passage done on heterologous host then it may adapt the virus and produce characteristic lesions in it. Further study will require to confirm host specificity of APVs.
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    ThesisItemOpen Access
    MOLECULAR PATHOMORPHOLOGY AND IMMUNODIAGNOSIS OF PPR IN GOATS IN ASSAM
    (AAU, 2016) Malik, Mahmuda; Rahman, Taibur
    Peste des petits ruminants is an acute viral disease of small ruminants caused by genus Morbillivirus and family Paramyxoviridae. The disease is characterized by fever, oculo-nasal discharges, stomatitis, diarrhoea and pneumonia. The present study was undertaken to observe the detailed pathology of the disease in natural cases with application of different diagnostic techniques viz., gross pathology, histopathology, ultrastructural study, histoenzymic study, cell culture study, indirect immunofluorescence antibody test and PCR technique . An experimental study was also conducted to study the progression of the disease in goats. In the present study a total of four outbreaks of PPR was attended and the experiment of the diseases was conducted in twelve animals, of which six were kept as control and the rest were treated with PPR antigen. Animals suspected of PPR in field condition showed various clinical signs, like oculo nasal discharge, erosive lesion at the muco-cutaneous junction, dyspnea, greenish diarrhoea and heavy mortality. A thorough necropsy examination revealed gross erosive lesions in the oral cavity, congestion and consolidation of the lungs, linear haemorrhage in the intestine, petechial haemorrhage on the spleen, swollen edematous lymph nodes and congestion in the brain. Histopathological study revealed necrosis, desquamation and ulcer formation on the epithelium lining the tongue and lips. Degeneration and depletion of lymphoid cells in the follicles of lymph node and spleen with presence of syncytia formation. Lungs showed broncho-interstitial pneumonia characterized by thickening of inter alveolar septa with infiltration by macrophages, lymphocytes, fibrosis and a few giant cells. Hyperplasia of the bronchial epithial epithelium with presence of both eosiniphilic intracytoplasmic and intranuclear inclusion bodies in the hyperplastic cells and in the desquamated bronchial and alveolar epithelium. Denudation of the intestinal villi with presence of infiltrating cells, glandular necrosis and depletion of peyer’s patches were present. Ultra structural study showed loss of the normal cell architecture with margination of chromatin in the nucleus. At higher magnification a large number of virion-like particles which appeared as electron dense bodies with a clear halo surrounding them were seen in the cytoplasm of cell. Histoenzymic study revealed mild lactate dehydrogenase activity in the degenerated cells of lymph node, spleen and in the tip of the hyperplastic bronchial epithelium. While intense alkaline phosphatase activity was seen in the affected lung and follicles of lymph node. Cell culture study showed development of cytopathic effects viz., rounding of cell, syncytia formation and elongation in a few cells with presence of intracytoplasmic inclusion bodies. Indirect immunofluorescence antibody test showed emission of apple green fluorescence emitting from the cytoplasm of the affected cells. Experimental studies of PPR infection in goats showed development of clinical sign viz., oculo-nasal discharge, fever, coughing, diarrhea, emaciation and eventually death. Gross and histopathological changes were almost similar to the lesions observed in natural cases. The ultra structural, histoenzymic, cell culture and indirect immunofluorescence studies were performed and the results observed were also similar to that of the natural cases. The haemato-biochemical study of the experimental animals revealed a lower level of total serum protein, with higher level of serum ALT and AST. Haematological study showed an increase in TEC, Hb and PCV, and a decrease in TLC and DLC.