Lone Star Tick

 Amblyomma americanum

Photo by CDC: Adult Female Lone Star Tick

This hard tick is not known as an established resident in Colorado, but has been documented on animals traveling with their owners from the eastern and midwestern US, where it has an extensive and expanding distribution, extending from Florida to Maine and as far west as Texas and Oklahoma.  This tick is high risk as an invasive species as demonstrated by its recent expansion to the northeastern region of the country. The adult female is distinguished by a white dot or “lone star” on her back. The lone star tick can transmit the agents of canine and human monocytic ehrlichiosis (HME), canine and human granulocytic ehrlichiosis (HGE), Tularemia, Q-fever and southern tick-associated rash illness (STARI); it has also been implicated in transmission of the Heartland and Bourbon viruses, and other Lyme-like illnesses. The bite of this tick may also cause potentially fatal host paralysis via toxins in their saliva, and bite may cause the Alpha-gal red meat allergies in a growing number of people. Hosts of this species include a wide variety of mammals and ground-dwelling birds. The nymph and adult females are the most common biters. This is an aggressive tick that frequently bites humans.

Visit University of Rhode Island’s TickEncounter Resource Center for additional photos to help in the identification of ticks.

CDC Distribution Map 2019: This map provides general insight into the expected distribution of these human-biting ticks in the contiguous United States. Populations of ticks may be found outside noted areas. Naturally occurring populations of the Lone Star Tick are not known to occur in Alaska or Hawaii.