Comparative pathomorphological, bacteriological and serological examination of broiler breeders and pheasants experimentally infected withOrnithobacterium rhinotracheale

Abstract

The aim of the investigations was to determine the influence of Ornithobacterium rhinotracheale (ORT) on the development of pathomorphological lesions in the respiratory organs and on the health status of experimentally infected broiler breeders and pheasants from the rearing stage. There was no evidence of clinical signs in infected broiler breeder hens nor in the group of infected pheasants except for one bird in the latter group which exhibited slower movement and gasping. The frequency and intensity of pathomorphological lesions were higher in pheasants. The gross pathology findings were characterized mainly by redness of the mucosa of the upper respiratory tract and accumulation of mucous content in the nasal cavities, infraorbital sinuses, larynx and trachea. Histopathology confirmed the presence of inflammation of the upper respiratory tract. Lesions in the lungs included hyperaemia, granulomatous and fibrinous pneumonia. ORT was reisolated only from the group of infected pheasants. Reisolation was successful from the respiratory organs (trachea, larynx, infraorbital sinuses, and lungs) of eight out of 10 infected birds. The serological response in both species was characterized by rapid production of specific antibodies that reached a maximum level in the blood in the first week after experimental infection. The antibody titres decreased gradually and were maintained at a stable level until the 12th week after inoculation. Fourteen weeks post-inoculation specific antibodies could not be detected by enzyme-linked immunosorbent assay.

Ornithobacterium rhinotracheale: An Update Review about An Emerging Poultry Pathogen

“…Of note, chickens and pheasants belong to the same family. The results showed a high similarity in the kinetics of serological responses for both species after infection, also confirming the use of this test in pheasants [24].…”

“…Factors, such as management, environmental stressors, or the presence of other pathogens, can play an important role in the disease manifestation [12]. Gavrilović et al [24] have demonstrated that natural monoinfections with ORT are less aggressive than those from experimental challenge. Experimental studies of monoinfection with ORT showed that ORT had less effect on hens than on pheasants, suggesting it is host dependent, although both species belonged to the same Phasianinae subfamily.…”

“…Many researchers have used serology to investigate ORT infections, but the results show wide variations. In the poultry industry, the presence of anti-ORT antibodies in chickens has been reported in many countries [2,15,22,24,27,28,36,37,41,52,[55][56][57]. Serology has advantages compared to bacterial isolation, since antibodies persist for several weeks after infection [5,12,53].…”

The first isolation and detection of Ornithobacterium rhinotracheale from swollen head syndrome-infected broiler flocks in Iraq

“…The previous studies also agreed with us based on their results [38]. We also found that a cycle threshold value of diffraction existed between the samples due to the differentiation of ORT's DNA in the sample [39].…”

Microscopic changes in the organs of broiler chickens with Ornithobacterium rhinotra-cheale infection

“…The pathological changes that are observed in ornithobacteriosis are usually localized to the lungs, and include thickening of the interstitial tissue, edema, effusion of exudate, fibrin, and heterophilic infiltration. In the trachea, as a rule, no specific pathological changes are observed, only sometimes lymphocytic, mononuclear infiltration of the mucous membrane, hyperplasia of the glandular epithelium are recorded (Gavrilović et al, 2015). A significant variation in the serovars of the pathogen and their variability significantly complicates the diagnosis of the disease in industrial poultry farming.…”