Spontaneous and Experimental Infection of Pigeons with B. Aertrycke.

Abstract

In the course of some studies upon blood-formation in pigeons, which had first been rendered anemic by fasting and then maintained upon various diets, several birds showed total white blood-cell counts varying from 60,000 to 187,000 cells per cmm. In the blood of these pigeons, myelocytes, varying from 2% to 70%, appeared. Coincident with the development of this striking change of the myeloid elements of the blood, these pigeons became acutely ill, rapidly developed an extreme degree of anemia (1,200,000 to 1,900,000 erythrocytes per cmm.) and died within less than a week after the apparent onset of their illness. In a series of 52 pigeons, 7 birds died in this manner.

Autopsies showed marked enlargement of the liver, spleen, and kidneys and massive hyperplasia of the bone-marrow. The liver and kidneys were studded with extensive infiltrations of myelocytes in which extremely young forms, frequently in mitosis, were present. In addition, large numbers of mononuclear phagocytes, frequently forming nodules, were found in the liver, spleen, kidneys, and bonemarrow. In these latter lesions numerous small, Gram-negative bacilli were regularly present, but no bacteria were ever demonstrated in the accumulations of myelocytes seen in the liver and kidneys. In none of the other 45 pigeons of the series were changes like these noted.

No adequate bacteriological studies were done upon the first 3 birds showing these lesions, but cultures of the blood, liver, kidney, and bone-marrow of the fourth bird (Pigeon 86) all gave pure growths of a small, Gram-negative bacillus, identified by Dr. L. T. Webster as B. aertrycke. An identical organism was recovered from the other 3 birds spontaneously developing the same disease.

The blood and tissues of Pigeon 86 were inoculated into 8 well-nourished, apparently normal pigeons. Three birds received 1 cc. each of blood given intravenously, two 2 cc. each of a heavy saline emulsion of liver, two 2 cc. each of a similar emulsion of bone-marrow, and a single bird was injected with 2 cc. of emulsion prepared from the kidney.