Establishment And Application Of Detection Methods For Gallibacterium Anatis And Study On The Pathology Of Oviduct Cysts

Gallibacterium anatis, which mainly infectes layers, is a latent pathogenic bacteria and has a certain relationship with oviduct cysts of chickens. From 2007 to 2010, based on the investigation of epidemiology in Henan, Anhui, Shanxi and Shandong provinces, PCR, fluorescence in situ hybridization (FISH) and histopathology were carried out to detect G.anatis from naturally and experimentally infected chickens. The detection methods developed above were rapid and specific and the pathology of chickens naturally and experimentally infected with G.anatis were observed in order to develop a pathology diagnostic method. This study provided a certain theory foundation for the differential diagnosis and the pathogensis of the disease of G. anatis. The results demonstrated that:1. The methods of PCR and FISH developed were used to detect G. anatis in blood, excreti -on and tissues of diseased chickens. The specificity and sensitivity of the methods were higher than bacteria isolation, and could be used to early detection and epidemiological investigation.2. The main necropsy findings were seen in the respiratory tract and genital tract of oviduct cysts, which affected the egg production and egg quality of layers; The pathological changes were peritonitis and different degree of oviduct cysts and the main histopathology were exfoliation of the mucosa epithelium cells, hyperaemia of cortex capillary and infiliatration of inflammation cells in up-respiratory tract; inflammation cells infiltrated in mucosa of magnum and uterus in oviduct, and nucleus of secretory cells broke into small pieces. The pathological changes of oviduct could be one of the important diagnosis points of the disease.3. SPF layers artifically infected with G.anatis showed the reproductive disorders, deforme -d eggs and lowered productivity. The dominant gross pathological lesions were seen in respiratory and genital tract, and pathological changes exhibited as hyperemia, oedema, serosity and inflammation exudation. The specific histopathology in magnum and uterine part of oviduct could be one of the important diagnostic character ofthe disease. It can be affirmed, from the above results, that the G. anatis, isolated from naturally occurring cases, had a certain pathogenicity, and this study provided some differential diagnosis for complicate co-infection in clinic.4. There was no change in egg production and quality, and no significant pathological chan -ges of 112-day layers infected with only E.coli. The combined infection with E.coli and G.anatis induced egg production dropped by 87.8%,poor quality of eggs increased by 75%; and the main histopathology changes were hemorrhage, congestion, lymphocyte cells and leukocytic infiltrate. E.coli and/or G.anatis infection caused an acute death of 164-day SPF layers; the symptoms of pericarditis, perihepatitis and peritonitis were recorded in the autopsy changes; and there was no significant histopathology expect trachea and lung.5. The pathological damage of SPF layers infected with both E.coli and G.anatis was more severe than only G.anatis infection. G.anatis mainly affected the egg production and quality of layers, and did not cause the death of chickens. It was concluded that E.coli and G.anatis had a certain synergism.This was the first study to induce the experimental cases infected with G. anatis and to research the pathological changes of naturally and experimentally cases. Furthermore, the results provided reference for the epidemiological investigation and differential diagnosis of G..anatis, and had very important academic and practical significance.