Occurrence of Sporadic Bacillemia in Experimental Tuberculosis in Dogs

Wilson 1 in summarizing the work on bacillemia in human tuberculosis up to 1933, concludes that bacillemia, detectable by present methods, is, except as a transitory phenomenon, rarely present until the disease has assumed an acute phase. Because of this discrepancy between the reported rare occurrence of bacillemia and the common demonstration of hematogenous tuberculous lesions at necropsy, it seems important to determine the frequency and significance of bacillemia as a transitory phenomenon in tuberculosis.

Corper, 2 using dogs as experimental animals, reports that large doses of tubercle bacilli given intravenously produced a rapidly fatal bacillemia without the formation of tubercles. Smaller doses of tubercle bacilli produced no bacillemia and no tuberculous lesions. A search of the literature reveals no report of daily blood-cultures over a period of several months, which would seem to be the most adequate means of determining the frequency of transitory or sporadic bacillemia.

In our experiment, dogs were used because of the relative ease of obtaining an adequate quantity of blood daily for culture, and because the relative resistance of the dog to tuberculosis is more closely parallel to that of the human, than is the low resistance of the rabbit and guinea pig.

Experimental tuberculosis was produced in dogs by the intravenous injection of large doses of a virulent human type of tubercle bacilli (H37) in a suspension of Kaolan, mineral oil, and normal saline. This method was found to produce embolic tubercles limited largely to the lungs and tending to heal or to progress slowly.

Tuberculous abscesses were produced by injection of a similar suspension of tubercle bacilli into the chest wall of dogs. These lesions tended to break down and discharge for a time and then heal.