Rhipicephalus sanguineus

Photo by CDC: Brown Dog Tick

This “species” of hard tick has a cosmopolitan distribution; recent studies suggest it is actually a complex of multiple species, some of which have not been described. This tick is unusual in that it is able to complete its entire life cycle indoors and has been shown to imbibe water directly, rather than having to use saliva to gather moisture from the air, as do other tick species. Unlike most other hard ticks, eggs of this tick are laid inside or near housing areas of animals, in cracks and crevices, rather than outside under vegetation. In Arizona, a population of this species has transmitted spotted fever group rickettsia to humans. Other disease causing agents transmitted by this tick include those of canine ehrlichiosis and canine babesiosis and other Rickettsia worldwide. In the US, Hosts species are primarily dogs, but also occasionally other mammals. Outside the U.S., this tick commonly infests a variety of domestic and wild mammals. This species is a biter of humans.

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

CDC Distribution Map: 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 Brown Dog Tick are not known to occur in Alaska, though isolated cases involving animal kennels have been noted; the Brown Dog Tick is endemic in Hawaii.