PNEUMONIA IN PIGS: A PATHOMORPHOLOGICAL STUDY
| dc.contributor.advisor | RAMADEVI, V (Major) | |
| dc.contributor.advisor | SRILATHA, Ch | |
| dc.contributor.advisor | ANAND KUMAR, P | |
| dc.contributor.author | LAVANYA, K | |
| dc.date.accessioned | 2016-12-23T14:23:38Z | |
| dc.date.available | 2016-12-23T14:23:38Z | |
| dc.date.issued | 2009-10 | |
| dc.description | THESES | en_US |
| dc.description.abstract | ABSTRACT : In India, pig rearing is very popular amongst the tribal, backward and weaker sections of the society. Apart from this, it is also taken up as intensive farming utilizing the agricultural by- products and garbage for the additional supplementation of income. India, with an estimated pig population of 14 million, ranks 11th and has around 1.41% of the World's pig population. Pneumonia is one of the most important diseases of pigs limiting their production. It causes economic losses by resulting in mortality, reduced growth rates and inefficient feed conversion. By studying the incidence, etiology and patho-morphological changes of pneumonia in pigs, proper control and preventive methods can be undertaken to reduce the economic losses. Keeping this in view, the present study was carried out to record the incidence and to study the etiology along with pathomorphological changes in various types of pig pneumonias. In the present investigation, a total of 350 pigs of either sex and of different age groups from various slaughter houses, field mortalities, private piggery farms located in and around Tirupati and Gannavaram towns and from postmortem examinations conducted at the Colleges of Veterinary Science in Tirupati and Gannavaram were subjected to detailed postmortem examination and the lung samples were collected. On gross and histopathological examination, 216 lungs revealed definitive lesions of various types of pneumonia, accounting to an incidence of 61.71%. Various types of pneumonic conditions that were observed in the pig lungs in the present study were broadly grouped into bronchopneumonia (81.01%), interstitial pneumonia (7.87%), bronchointerstitial pneumonia (8.33%), granulomatous pneumonia (0.46%) and verminous pneumonia (2.31%) types. Of these, bronchopneumonia cases were further subdivided into acute suppurative bronchopneumonia (76.57%), chronic suppurative bronchopneumonia (8.57%), fibrinous bronchopneumonia (12.0%) and necrotizing bronchopneumonia (2.85%) cases basing on the predominance of exudates composed of either neutrophils or fibrin. Acute suppurative bronchopneumonia cases were characterized by cranioventral consolidation in the apical and cardiac lobes grossly and alveolar congestion, edema, presence of inflammatory cellular exudates in the lumen of the bronchi, bronchioles and alveoli consisting of abundant neutrophils, few macrophages and cellular debris and acute bronchiolitis microscopically. The bronchial lymph nodes were haemorrhagic. E.coli, Pseudomonas sps, Pasteurella sps, Streptococcus sps, Salmonella sps and Klebsiella sps were isolated from acute suppurative bronchopneumonia cases. Chronic suppurative bronchopneumonia cases showed lobular pattern of consolidation cranioventrally with small purulent foci or abscesses grossly. The microscopic lesions like infiltration of neutrophils in the lumen of bronchioles and alveoli, fibrosis of the alveolar septa and areas of suppuration with abscess formation were noticed. In some abscesses, the oat cells were streaming at the margins of the purulent centres. Coagulase positive Staphylococci were majorly isolated from abscesses. Streptococcus sps, E.coli, coagulase negative Staphylococcus and Bacillus sps were the other organisms isolated from these cases. Fibrinous bronchopneumonia cases were characterized grossly by cranioventral consolidation, prominent interlobular septa and thickened pleura. Microscopically, alveoli revealed serofibrinous exudates, red blood cells, few neutrophils and mononuclear cells. The interlobular septa were dilated, edematous along with congested blood vessels and dilated lymphatics and filled with fibrin. The pleura were markedly thickened due to fibrinous exudates and slight proliferation of fibroblasts and haemorrhages were noticed in the bronchial lymph nodes. Pasteurella sps were the major organisms isolated from these cases and Pseudomonas sps and E. coli were the other organisms. Necrotizing bronchopneumonia cases showed irregular shaped nodules that revealed necrosis grossly. Microscopically, areas of coagulative necrosis with accumulation of polymorphs showing karyorrhexis of the nuclei at the periphery were evident. Ectatic and ectatic like bronchioles were filled with necrotic material with a continuous layer or fragments of bronchiolar epithelium. Coagulase positive Staphylococci and Pseudomonas sps were the major organisms isolated from these lesions and the other organisms isolated were E. coli, Pasteurella sps and Streptococcus sps. The lungs were pale, heavy and firm with elastic or rubbery texture grossly in interstitial pneumonia cases. The microscopic lesions noticed were thickened alveolar septa and alveoli lined by cuboidal epithelial cells and filled with mononuclear cells, macrophages and desquamated epithelial cells. Presence of extensive lymphoid follicular aggregates in the peribronchial, peribronchiolar and perivascular spaces and peribronchial and perivascular fibrosis were also noticed. Salmonella sps were the organisms isolated majorly from these cases and Streptococcus sps, E. coli, Proteus sps, Klebsiella sps and coagulase negative Staphylococcus were the other organisms isolated. Grossly, the lungs in the bronchointerstitial pneumonia cases were heavy, edematous, reddened, consolidated throughout and failed to collapse when thorax was opened. Microscopically, the presence of both bronchiolar and diffuse alveolar damage, desquamation of bronchial epithelium and an influx of neutrophils into the alveolar lumen were noticed. The alveoli were lined by cuboidal type II pneumocytes. The lymph nodes revealed congestion, haemorrhages and depletion of lymphocytes in the lymphoid follicles. Classical swine fever virus was demonstrated along with secondary bacterial infections like Pasteurella sps, E. coli and Streptococcus sps in the bronchointerstitial pneumonia cases. Granulomatous pneumonia case was characterized by the presence of small granulomas in the lung consisting of a foreign body in the center surrounded by epithelioid cells, macrophages, eosinophils, lymphocytes and with an outer rim of connective tissue. E.coli and coagulase negative Staphylococcus were isolated from this case of pneumonia. Verminous pneumonia cases revealed small grey nodules in the cranioventral border of the diaphragmatic lobes of the lungs with the presence of adult worms belonging to Metastrongylus sps grossly. Microscopically, the presence of parasitic sections in the lumen of the bronchioles and thickened alveolar walls by infiltrated mononuclear cells and multinucleated giant cells were noticed. The bronchial epithelium was desquamated and eosinophils, lymphocytes and neutrophils infiltrated the mucosa. Peri bronchiolar and perivascular fibrosis was noticed in the chronic cases. In total, 67 primary isolates of bacteria were obtained in the present study from various types of pneumonias. Pasteurella sps (20.89%) were the major organisms isolated followed by E.coli (17.91%), Pseudomonas sps (13.43%), Streptococcus sps (13.43%), coagulase positive (11.94%) and negative (7.46%) Staphylococci, Salmonella sps (7.46%), Klebsiella sps (2.98%), Bacillus sps (2.98%) and Proteus sps (1.49 %). Immunohistochemical staining of few lung sections was carried out with antibodies to cytokeratin, CD4, CD8, CD68 and plasma cell (IgG1) markers. Intense specific staining for cytokeratin was noticed in the cytoplasm of epithelial cells of bronchi, alveoli and the bronchial glands in pneumonic lungs when compared to the normal lungs. The tissue sections from pneumonic lungs also revealed the presence of CD4+ and CD8+ lymphocytes and CD68+ macrophages and IgG1 positive plasma cells in the peribronchial areas. Transmission electron microscopic studies conducted on samples of lung tissues showing interstitial pneumonia in the present study revealed the ultrastructural changes like thickening of inter alveolar septa, lymphoid hyperplasia in BALT, proliferation of Type II pneumocytes and heavy infiltration of inflammatory cells. The lymphocytes revealed distribution of chromatin towards margins and vacuolation in the nucleolemma and cytoplasm. Different shapes of nuclei and prominent chromatin materials were noticed in the macrophages. Type II pneumocytes showed degenerative changes like vacuolation in cytoplasm and nucleus, margination of chromatin material, clumping of outer and inner nuclear membranes, swollen mitochondria with loss of cristae, dense and thickened rough endoplasmic reticulum and electron dense bodies without any encapsulation in the cytoplasm. The present investigation revealed that pneumonia is a major health problem in pig population in the area of study with an incidence of 61.71 %. It was also evident that the etiology is complex and multifactorial. The pathomorphological changes indicated that the pneumonias can result in high morbidity and mortality leading to economic losses. | en_US |
| dc.description.sponsorship | DEPARTMENT OF VETERINARY PATHOLOGY , COLLEGE OF VETERINARY SCIENCE , SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI – 517 502. (A.P.) INDIA | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/92464 | |
| dc.language.iso | en | en_US |
| dc.publisher | Sri Venkateswara Veterinary University, TIRUPATI – 517 502,A.P | en_US |
| dc.sub | Veterinary Pathology | en_US |
| dc.subject | PIGS; PNEUMONIA; PATHOMORPHOLOGICAL STUDY | en_US |
| dc.title | PNEUMONIA IN PIGS: A PATHOMORPHOLOGICAL STUDY | en_US |
| dc.title.alternative | MVSC;CVSc;TPTY; Acc No:T1307 | en_US |
| dc.type | Thesis | en_US |