Spirochetes believed to be the cause of
Lyme disease were isolated from white-footed mice and white-tailed deer, the preferred natural hosts of Ixodes dammini, the tick vector. Evidence suggests that deer act as a reservoir of the
disease and provide an overwintering mechanism for both spirochetes and adult ticks. Some tick larvae may acquire the spirochete by transovarial passage and the nymphal stage may transmit the
disease to humans.