by Microbe Fan
The deer tick, Ixodes scapularis. Photo: Scott Bauer, USDA
Agricultural Research Service, Bugwood.org. Source.
In the northeastern United States the Lyme disease spirochete Borrelia burgdorferi spreads from one white-footed mouse to another by hitching a ride in the deer tick Ixodes scapularis. Transmission between tick and mouse occurs during the tick's rare blood meals. The larval tick acquires B. burgdorferi from an infected mouse during a blood meal late in the summer, and the spirochetes take up shelter in the tick's midgut. Later the larva molts into a nymph, which then completes the transmission cycle by feeding on an uninfected mouse during the next spring or early summer.
Although blood is potentially a rich source of nutrients for both tick and spirochete, the cells lining the tick's gut rapidly engulf the nutrients, including glucose, an energy-rich sugar favored by B. burgdorferi. The spirochetes must therefore rely on other energy sources if they are to survive the many months between tick feedings. How does B. burgdorferi fuel its survival during this period?