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==Pathogenic Activity==
Coxiella burnetti does not display a pathogenic effect for all organisms it encounters. For example, B. La Scola and D. Raoult discovered that Coxiella burnetti and free-living amoeba Acanthamoeba castellanii are able to co-exist in a benign relationship upon infection. The bacterium was able to produce spore-like structures in vacuoles within the amoeba, demonstrating its ability to differentiate without any interference from the other species. The bacterium does not cause any diseases in the amoeba. Likewise, the amoeba did not utilize the bacterium as food, so it contributes to the survival of Coxiella burnetti by supplying an intracellular niche for it to differentiate into a structure similar to a spore and resist harmful environmental conditions.

Besides surviving in a host cell, Coxiella burnetti can adapt to a shared intracellular niche with another parasite without inhibition of development for either. According to research accomplished by Andreoli and colleagues, Vero cells that were previously inhabited by Coxiella burnetti were co-infected with another type of parasite such as Trypanosoma cruzi. Parasitophorous vacuoles (PV) of T. cruzi trypomastigotes and bacterial vacuoles fused together upon co-infection. T. cruzi was able to proceed with differentiation into amastigotes and division in Coxiella burnetti vacuoles. The co-existence of both parasites depends on the ability of Coxiella burnetti to provide sufficient amount of nutrients for T. cruzi.