Propagation and quantification of obligate intracellular pathogens are both labor-intensive and costly. These characteristics, coupled with C. burnetifs highly infectious nature and select agent designation, complicate the most basic research endeavors. However, because highly purified and enumerated C. burnetii"\s essential to the proposed research, a dedicated core facility with BSL-3 containment, highly trained technical personnel, and an archival system is proposed. Thus, the purpose of the Core is to make available to each of the 4 projects expertise in the cultivation, enumeration, and archival of phase 1 and 2 Coxiella burnetii. The core will be located at Montana State University, the location of the BSL-3 facilities, but will be headed by Mike Minnick of the University of Montana. Collaborations among projects. Core A will provide services to each of the 4 projects of the Program Project. These services will include making standardized inocula of phase 1 and 2 Coxiella available to all the cores, as well of the services of Coxiella enumeration and archival of Coxiella organisms. In addition, projects 2, 3 and 4 have no experience with working with Coxiella, thus, the Core will provide this additional critical service to those projects. Therefore, the core is integral and critical to the goals of each of the projects and the goal of the Program Project.