Carrie Mae Long, Ph.D.

This pseudo-colored transmission electron micrograph shows Coxiella burnetii infecting an African green monkey cell line, forming a large vacuole (green) in the host cell 8 days following primary inoculation. This occurs in the absence of any overt detriment to the host, exemplifying the bacterium’s ability as a stealth pathogen.

Credit: NIAID

Coxiella burnetii is a highly infectious, zoonotic bacterial pathogen that causes a potentially debilitating febrile illness in humans called Q fever. C. burnetii is remarkably environmentally stable and typically causes Q fever via aerosol transmission. Bacterial pathogens with these attributes pose a threat to human health both due to potential bioterrorism and incidental exposure. Indeed, in 2007 a Q fever outbreak occurred in the Netherlands, resulting in nearly 4,000 human cases. This outbreak demonstrated the human health burden and the economic losses that can result from this disease, which is endemic worldwide.

Our group seeks to gain a better understanding of bacterial and host factors involved in C. burnetii virulence. Additionally, we are focused on developing a “better” Q fever vaccine. The current Q fever vaccine is highly efficacious but can cause a post-vaccination hypersensitivity (PVH) response; thus, the vaccine is not widely deployed. We seek to understand the immunologic mechanisms underlying vaccine-mediated protection and the PVH response. We primarily use in vivo models of disease and bacterial genetic manipulation to achieve these research goals. Currently, we are expanding the guinea pig model, which serves as the superior small animal model for Q fever. Ultimately, our research goals are aimed at understanding the host-pathogen relationship between humans and C. burnetii, which may lead to the development of novel preventative measures for Q fever.