Scanning electron photomicrograph; x1,000 approximate magnification; post-capture digital colorization

Eye of Science, Reutlingen, Germany

A macrophage, or white blood cell (shown in yellow), is observed attacking a group of Borrelia sp. bacteria (colored blue, lower left). Various types of Borrelia sp. bacteria cause conditions such as Lyme disease and relapsing fever. The macrophage here has extended a long pseudopod towards the bacteria prior to engulfing them. Once engulfed the bacteria will be destroyed through a process known as phagocytosis, a type of chemical digestion. Macrophages combat many types of foreign organisms that infiltrate the body, including bacteria.