American Dog Tick

American dog tick (Dermacentor variabilis) is the most commonly identified species responsible for transmitting Rickettsia rickettsii, which causes Rocky Mountain spotted fever in humans. The American dog tick can also transmit tularemia. This tick is widely distributed east of the Rocky Mountains and also occurs in limited areas on the Pacific Coast. D. variabilis larvae and nymphs feed on small rodents. Dogs and medium-sized mammals are the preferred hosts of adult D. variabilis, although it feeds readily on other large mammals, including humans.

Brown Dog Tick

The brown dog tick (Rhipicephalus sanguineus) has recently been identified as a reservoir of R. rickettsii, with all life stages causing Rocky Mountain spotted fever, in the southwestern U.S. and along the U.S-Mexico border. Brown dog ticks are found throughout the U.S. and the world. Dogs are the primary host for the brown dog tick for each of its life stages, although the tick may also bite humans or other mammals. Both nymphal and adult stages can transmit the agents of canine ehrlichiosis (Ehrlichia canis) and canine babesiosis (Babesia canis vogeli and Babesia gibsoni-like) to dogs.

Western Black-legged Tick

The western blacklegged tick (Ixodes pacificus) can transmit the organisms responsible for causing anaplasmosis and Lyme disease in humans. Wild rodents and other mammals are likely reservoirs of these pathogens. This tick is distributed along the Pacific coast of the United States. Larvae and nymphs feed on birds and small rodents, while adult ticks feed on deer and other mammals. Both adult and nymphal ticks are known to transmit disease to humans.

Black-legged or Deer Tick

The blacklegged tick (Ixodes scapularis), commonly known as a “deer tick”, can transmit the organisms responsible for anaplasmosis, babesiosis, and Lyme disease. Adult males and females are active October-May, as long as the daytime temperature remains above freezing. Preferring larger hosts, such as deer, adult blacklegged ticks can be found questing about knee-high on the tips of branches of low growing shrubs. Nymphs also readily attach to and blood feed on humans, cats and dogs.

Rocky Mountain Wood Tick

Rocky Mountain Wood ticks are found predominantly in shrublands, lightly wooded areas, open grasslands, and along trails, mainly at lower elevations. All life stages of this tick can transmit Colorado tick fever virus (CTFV) to humans, and Rocky Mountain spotted fever (RMSF) rickettsia (Rickettsia rickettsii) to humans, cats, and dogs. This tick is found in the Rocky Mountain states. Adult ticks feed primarily on large mammals. Larvae and nymphs feed on small rodents. Adult ticks are primarily associated with pathogen transmission to humans.

Lone Star Tick

Lone Star ticks are found mostly in woodlands with dense undergrowth and around animal resting areas. The larvae do not carry disease, but the nymphal and adult stages can transmit the pathogens causing Monocytic Ehrlichiosis, Rocky Mountain Spotted Fever and ‘Stari’ borreliosis. Lone Star ticks are notorious pests, and all stages are aggressive human biters. Females are easily recognized by a single white dot in the center of a brown body, with the males having spots or streaks of white around the outer edge of the body.