Studies on the Pathogenesis of Brucellosis. ∗

Abstract

Conclusions

The studies referred to, and our own observations in experimental brucellosis are in our opinion, good evidence of the ability of Brucella to use the cytoplasm of a variety of cells as a source of material for its growth. The fact that even in the early stages of the infection, when the hosl has not developed immunity against brucellae, important groups of this organism are found only within the cytoplasm of certain cells, seems to indicate that the intracellular growth is the most convenient for the preservation of the infecting agent. When the intracellular colony has reached its maximum, the cells are destroyed and the brucellae exposed to unfavorable conditions, namely to phagocytosis by polymorphonuclear leucocytes. From the scarcity of extracellular organisms one may think that the intracellular fluids are not suitable for an active multiplication of Brucella, exception is made of zones where the tissues have been subject to considerable damage. In these zones one may find extracellular Brucella in large numbers. One would consider that the organism could be placed together with true intracellular parasites, but this is not the case since Brucella have its own enzyme systems with which it is able to use rather ordinary material for its metabolism.

Considering as likely that in man Brucella grow in a manner similar to that which has been observed in the experimental infection, the pathogenesis of the disease seems to us better understood.