STUDIES ON EXPERIMENTAL MYCOPLASMOSIS IN CHICKENS : II. PATHOLOGICAL FINDINGS OF CHICKENS INOCULATED WITH MYCOPLASMA GALLISEPTICUM (STRAIN S₆)BY THE AIR-SAC AND INTRAVENOUS ROUTES

Abstract

Over a period from 1964 through 1968 a series of experiments on mycoplasrnosis in?chickens were carried out to investigate clinical signs, anatomico- and histopathologicallesions, and recovery of the organism inoculated. In them, chickens were inoculated withrMycoplasma gallisepticum (MG) directly into tlae posterior thoracic air-sac (PAs), intra-venously (IV) into the wing vein, or by the combined routes, PAs and IV. The resultsof the clinical observation and recovery of the inoculated organism from tlae chickenswere reported in a previous papers).The objectives of the present experiments were (l) to examine the [esions of theair-sac and other organs and tissues of chickens following inoculation with the organismand (2) to determine differences in lesions of chickens inoculated among the three types, of inoculation. The outline of the experiments is given in Table l to 4. The materialsand methods used in the present experiments were the same as mentioned in the previouspaper20). Tlte results obtained are summarized as follows.l. Lesions caused by MG inoculated into the PAs were generally mild in nature.They were found mainly in the respiratory organs, including the air-sacs, and subsequentlyin the spleen. After intravenous inoculation with MG, proliferation of lymphoreticulartissues produced characteristic lesions in the spleen and liver. No lesions, however, werefound in any of the air-sacs.2. Primary lesions found 6 hours after .lV[G inoculation into the PAs howed thickening of the air-sac due to new formation of bl6od capillaries, edema, congestion, and infiltration of monocuclear leukocytes. The most conspicuous lesions in the air-sacs examined?on the 7th day after exposure showed a tendency to undergo repair approximately onthe 12th day after inoculation.3. After intravenous inoculation with MG, lesions were found mainly in the spleen, liver, and respiratory organs, except the air-sacs. In a few cases mild inflammatory reac, tions were found to have occurred in the intestines, heart, kidneys, pancreas, crop