抄録
In the previous investigationt, tlae authors studied a respiratory disease of rats andshowed that some species of Mycoplasma miglat be associated with the disease. Thepresent experiment was carried out over a period from December, 1965, to July, 1966, to study the difference in contaminatiorn with Mycoplasma due to breeder farm stock, age, and sex of rats. The results obtained are summarized as follows.l. Only the rats of breeder SD were found to be free from Mycoplasma amongthose of the six breeder farm stocks examined. The rats of breeders C and D werefound to be contaminated witlt Mycoplasnna at a higher rate than tlnose of breeders A, B, and E. Amorig the breeder farm stocks of A, B, and E, however, no difference wasrecognized in the rate of isolation of Mycoplasma.2. Among the rats of breeders A, B, and E, the adults were found to be contami-nated with Mycoplasma at a higher rate than the young. Among the rats of breeder D, no age difference was found.3. In adult rats, Mycoplasma was isolated from males at a higlaer rate tlaan females.No sex difference was found, however, in young ones.4. The rate of isolation of Mycoplasma from the respiratory tract was the higl?estin the nasal cavity, the second highest in the bronchi, and the lowest in the lung.5. When the data were examined statistically, no relationsltip was recognizedbetween Mycoplasma and the gross Iesion in the lung. FurtI?ermore, a relationsltip wasdiscussed between this gross lesion and Mycoplasma or clinical findings in all therespiratory system.
