| Abstract: | A one-time, orally administered dose of greater than or equal to 1 X 10(6) colony-forming units of Mycoplasma mycoides subspecies mycoides was sufficient to induce clinical mycoplasmosis (n = 37) terminating in fatal mycoplasmemia in 73% (37 of 51) of the clinically affected kids. The pathogen was isolated from the blood samples as early as 24 hours after oral inoculation; hot, swollen joints frequently were evident by 4 or 5 days after exposure. Pyrexia (to 42.3 C) was detected in about 95% (35 of 37) clinically affected kids, although about 5% (2 of 35) died peracutely without fever or other premonitory signs. At necropsy, the cardinal lesions were a fibrinopurulent polyarthritis and red, patchy to diffuse areas of consolidation in 1 or more lung lobes. At death, usually within 4 to 16 days after oral inoculation, the concentration of M mycoides subspecies mycoides in the blood was 1 X 10(6) to 1 X 10(7) colony-forming units/ml. Histologically, the kids had diffuse fluid leakage into pulmonary alveoli and to a lesser extent into small vessels of various other organs. Fibrinocellular thrombi of terminal occurrence were occasionally present in various organs. The meningeal, pleural, and peritoneal surfaces had vascular leakage and a minimal perivascular accumulation of leukocytes. The disease was contagious. Of 14 noninoculated control kids in close confinement with affected kids, 8 (57%) developed mycoplasmosis in 7 to 15 days and died of mycoplasmemia. The remaining 5 noninoculated kids remained healthy, as did noninoculated kids that were kept isolated from affected kids. |
