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Brown dog tick

Tick ID

Brown dog tick

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Brown dog tick

Rhipicephalus sanguineus


This “species” of hard tick has a cosmopolitan distribution, including collection records from every state in the USA, via its association with domestic dogs. Recent studies suggest it is actually a complex of multiple species, some of which have not yet been described.  In CO, this tick may be associated with domestic dogs recently brought in from out-of-state, but established local infestations may persist indoors anywhere (e.g., kennels). 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 (kennels), and in cracks and crevices of buildings, rather than outside under vegetation.


In the US, host species are primarily dogs, but occasionally other mammals, including humans. Outside the US, this tick commonly infests a variety of domestic and wild mammals.

Vector Status

In addition to causing tick paralysis in dogs, they are vectors of multiple canine and human disease agents. Disease agents allegedly transmitted by this tick include those causing canine ehrlichiosis, canine babesiosis via multiple Babesia spp.; canine hepatozoonosis, Hepatozoon canis (Hepatozoidae); haemotropic mycoplasmosis, Mycoplasma haemocanis (Mycoplasmataceae) (experimental transmission only); Q Fever; tularemia; babesian and theilerian equine piroplasmosis; Mediterranean spotted fever, Rickettsia conorii; and another spotted fever, R. massiliae. Populations of brown dog ticks in Arizona and adjacent northwestern Mexico are uniquely known vectors of the agent of Rocky Mountain Spotted Fever to humans, especially on reservation lands.


H Joel Hutcheson, James W Mertins, Boris C Kondratieff, Monica M White, Ticks and Tick-Borne Diseases of Colorado, Including New State Records for Argas radiatus (Ixodida: Argasidae) and Ixodes brunneus (Ixodida: Ixodidae)Journal of Medical Entomology, tjaa232,

Centers for Disease Control and Prevention

Colorado Department of Public Health and Environment webpage and personal communication, with Dr. Leah Colton (former CDPHE, Entomological Epidemiologist).

Brown dog tick

Tick ID
Photo by CDC

Brown dog tick life stages and engorgement

Brown dog tick life stages and engorgement, CDC photo
CDC Photo, Brown dog tick life stages and engorgement

American dog tick distribution in Colorado: 2014-2019

Brown Dog Tick Distribution Mapin Colorado
Occurrence Map from Colorado Department of Public Health and Environment: 2014-2019 collections

Brown dog tick distribution in US: 2019

CDC Distribution Map for Brown Dog Tick
CDC Distribution Map: This map is not meant to represent risks for a specific tick-borne disease, because disease transmission is influenced by multiple factors beyond mere tick presence. This map has been designed to answer the question “What ticks should I be concerned about at a regional scale?” Please consult a local public health authority or USDA Agricultural Extension Office to determine more specific information at the state, county, or municipal level. Background data for this map is from the US National Atlas. 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.