Spirochetes are gram-negative chemoheterotrophic bacteria. They have slender bodies that allow them to move through viscous solutions, even though they lack flagella. They are also capable of crawling over solid surfaces. Spirochetes have very diverse physiologies including aerobic, anaerobic, and facultative anaerobic ways of life. As might be expected, they occupy a wide array of habitats including both marine and freshwater settings. Some species form symbioses with molluscs, mammals, or protozoans.
Lyme disease, which is caused by the spirochete, Borrelia burgdoferi, is becoming more prevalent worldwide, not excluding the Arctic. Larval ticks hatch and feed on infected rodent blood. Later, in their nymphal stage, they live on birds or mammals for two years until they are fully grown. Adults subsequently attach to a new host, feed on it, and infect it. Seabirds maintain the life cycle of B. burgdoferi by transmitting the vector (ticks) between islands in the Arctic Archipelago. Lyme disease affects the musculoskeletal and neurological systems, and the joints, of infected humans.