Ticks, part of the arachnid family, can be found on every continent. They feed on the blood of their hosts which range from birds and reptiles to mammals both large and small. Of the nearly 900 tick species across the globe, 8 are of major concern in the transmission of tick-borne diseases to humans in North America.
Though habitat varies from region to region, most ticks prefer to live in areas with dense undergrowth, long grass, leaf litter, fallen logs, and the edge of woods. Ticks don’t jump or fall out of trees. They move short distances on their own or on small mammals. Long-distance travel is by deer or birds. Blacklegged ticks don’t go and find a host, instead, they wait for it to come to them. These ticks crawl out to the edge of vegetation, wait for something to pass by, and then grab on to whatever brushes into them.
The ticks shown here are the primary vectors of tick-borne diseases in North America.
Transmits: Lyme disease, anaplasmosis, babesiosis, Powassan disease, Borrelia mayonii disease, Borrelia miyamotoi disease, Ehrlichia muris-like disease, and possibly bartonellosis disease.
Geographic distribution: Northeast, upper Midwest, from the Gulf Coast westward to central Texas
Life Cycle of Blacklegged Tick
- Larva hatch from eggs in the spring of year 1 and seek a meal
- Once fed, they molt into nymphs and essentially sleep until the spring of year 2
- They take a second meal and molt into adults
- Adults mate and the male then dies
- The female takes a third meal before laying eggs
- Once she lays her eggs the next spring, she dies and the cycle repeats itself
Transmits: Lyme disease, anaplasmosis, babesiosis, B. miyamotoi disease, Human Monocyctic Ehrlichiosis (HME), and possibly bartonellosis disease.
Geographic distribution: Pacific coast and western states.
Transmits: Rocky Mountain spotted fever, Tularemia
Geographic distribution: Primarily found east of the Rocky Mountains and along the West Coast
Transmits: Rocky Mountain spotted fever
Geographic distribution: Nationwide
Transmits: Human Monocyctic Ehrlichiosis, Southern rash illness (STARI), Tularemia, Heartland virus
Geographic distribution: Eastern, Southern and Midwestern states
Common name: Pacific Coast Tick
Transmits: Rocky Mountain spotted fever, Tularemia, 364D rickettsiosis
Geographic distribution: Southwestern Oregon, California and Baja, Mexico
Common name: Gulf Coast Tick
Transmits: Spotted fever group rickettsia
Geographic distribution: Costal areas of the southern United States
Common name: Rocky Mountain Wood Tick
Transmits: Rocky Mountain spotted fever, Tularemia, Colorado tick fever virus (CTFV)
Geographic distribution: Northwestern U.S.