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.

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Common names: Blacklegged or Deer Tick

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
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Common name: Western Blacklegged Tick

Transmits: Lyme disease, anaplasmosis, babesiosis, B. miyamotoi disease, Human Monocyctic Ehrlichiosis (HME), and possibly bartonellosis disease.

Geographic distribution: Pacific coast and western states.

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Common names: American Dog Tick

Transmits: Rocky Mountain spotted fever, Tularemia

Geographic distribution: Primarily found east of the Rocky Mountains and along the West Coast

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Common name: Brown Dog Tick

Transmits: Rocky Mountain spotted fever

Geographic distribution: Nationwide

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Common name: Lone Star Tick

Transmits: Human Monocyctic Ehrlichiosis, Southern rash illness (STARI), Tularemia, Heartland virus

Geographic distribution: Eastern, Southern and Midwestern states

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Common name: Pacific Coast Tick

Transmits: Rocky Mountain spotted fever, Tularemia, 364D rickettsiosis

Geographic distribution: Southwestern Oregon, California and Baja, Mexico

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Common name: Gulf Coast Tick

Transmits: Spotted fever group rickettsia

Geographic distribution: Costal areas of the southern United States

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Common name: Rocky Mountain Wood Tick

Transmits: Rocky Mountain spotted fever, Tularemia, Colorado tick fever virus (CTFV)

Geographic distribution: Northwestern U.S.