Study of the Growth and the Pathogenicity of Mycoplasma and Adenovirus Infections of Avian Tracheal Explants.

Studies essentially involved examination of the structural details of the pathogenicity of single and mixed infections of mycoplasma and CELO virus in tracheal explants and infected chickens. The first part of the work concerned study of the growth response of the parasites in explants, alone or together. This was followed by study by light and electron microscopy of their effects, and interaction with the explants. Tracheal specimens from infected birds were also examined for any evidence of pathogenicity similar to that found in explants. In the explants there was evidence for interference between the growth of the parasites but only with Mycoplasma gallisepticum were extensive cytopathological effects detected. Mycoplasma gallinarum also caused some damage to the tissues but by a mechanism which appeared to be different to that associated with M. gallisepticum, which early on developed an intimate relationship with the cells. Structural differences between the two mycoplasmas were also detected in the scanning and transmission electron microscope which probably related to their functional activities. CELO virus was virtually without effects on the explants although viral material was seen in many epithelial cells, and there was little evidence for a synergistic relationship between virus and mycoplasma. No morphological evidence of mycoplasma or virus was found in the trachea of infected birds and the pathogenic effects, which were detected, seemed to reflect more on the treatment the birds experienced at infection than on the activities of the parasites