Host and Bacterial Factors Control Susceptibility of Drosophila melanogaster to Coxiella burnetii Infection

is the causative agent of Q fever, a zoonotic disease that threatens both human and animal health. Due to the paucity of experimental animal models, little is known about how host factors interface with bacterial components and affect pathogenesis. Here, we used , in conjunction with the biosafety level 2 (BSL2) Nine Mile phase II (NMII) clone 4 strain of , as a model to investigate host and bacterial components implicated in infection. We demonstrate that adult flies are susceptible to NMII infection and that this bacterial strain, which activates the immune deficiency (IMD) pathway, is able to replicate and cause mortality in the animals. We show that in the absence of Eiger, the only known tumor necrosis factor (TNF) superfamily homolog in , -infected flies exhibit reduced mortality from infection. We also demonstrate that the type 4 secretion system (T4SS) is critical for the formation of the -containing vacuole and establishment of infection in Altogether, our data reveal that the TNF homolog Eiger and the T4SS are implicated in the pathogenesis of in flies. The /NMII model mimics relevant aspects of the infection in mammals, such as a critical role of host TNF and the bacterial T4SS in pathogenesis. Our work also demonstrates the usefulness of this BSL2 model to investigate both host and components implicated in infection.