The Lowdown on Lyme Disease
The Ixodes scapularis ticks that transmit Lyme disease in
Eastern regions of the United States and Canada have a
two-year life cycle. It begins in early spring, when adult
females lay eggs on the ground. The eggs hatch as
temperatures warm, and the miniscule larvae feed on mice
and other small animals until early fall. They then molt
into nymphs and rest through winter in leaf litter, under
rocks or woodpiles, or anywhere they can find cover. The
following spring, nymphs, which are responsible for the
majority of Lyme disease cases in humans because of their
small size, emerge. In the fall these nymphs molt into
adults. The adults typically climb to tips of grass or onto
shrubs to better grab onto deer (or another large mammal)
as a place to feed and mate. Once mated, the females drop
off, lay eggs, and the cycle begins again.
