Scanning electron micrograph of a murine macrophage infected with Francisella tularensis (strain LVS), the causative agent of tularemia, also known as rabbit fever. Macrophages were dry-fractured by touching the cell surface with cellophane tape after critical point drying to reveal intracellular bacteria. Francisella tularensis cells (colorized in blue) are located either in the cytosol or within a membrane-bound vacuole (image by the National Institute of Allergy and Infectious Diseases, National Institutes of Health (USA); the image was modified by MIC). The cover is published under the Creative Commons Attribution (CC BY) license.