If there’s one thing you don’t want to bring home with you after a trip outdoors, it’s a tick. This pesky arachnid thrives in the summer, and it's the primary culprit of Lyme disease in Massachusetts.
There are two species of ticks common in Massachusetts—the Deer Tick (Ixodes scapularis) and the Dog Tick (Dermacentor variabillis). An adult Deer Tick is substantially smaller than the more common Dog Tick.
However, size is not always a useful indicator since an engorged tick can be several times the size of one that has not fed.
And while only Deer Ticks carry Lyme disease, it is far better to avoid ticks altogether than to attempt to differentiate between the two species.
Deer Ticks have a two-year lifespan, and have three feeding stages—larva, nymph, and adult. Eggs are laid in the spring, and in the summer they hatch into larvae no larger than the period at the end of this sentence.
In August, the larva reaches its peak of activity, waiting on the ground until a suitable host (bird or mammal) brushes up against it. The larva then attaches itself to the host. If the host animal is infected with the bacterium that causes Lyme disease, then the larva becomes infected as well.
Once it has fed, the larva does not feed again until it becomes a nymph. Therefore, larvae aren't able to transmit Lyme disease.
The larva molts and transforms into a nymph in the fall. The nymph doesn't become active until the following May, and it remains active through July. As in the larval stage, the nymph waits for a host to brush by so it can attach itself.
Once attached to a host the nymph will feed for 4-5 days, engorging itself with blood until it is several times its original size. If the tick was infected with the bacterium as a larva, the nymph may transmit it to its host. Since a nymph is only the size of a poppy seed, it's often goes unnoticed until it's fully engorged.
The nymph stage is responsible for the majority of human Lyme disease cases.
Situations & Solutions
Lyme disease is caused by a "spirochete" (corkscrew-shaped bacterium) called Borrelia burgdorferi. The bacterium is transmitted to humans by infected ticks in the genus Ixodes—in Massachusetts, that's the Deer Tick.