Regional tick guide

Ticks in Colorado

Explore reviewed tick occurrence records for Colorado, with links to identification profiles, evidence and practical guidance.

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Reviewed sources

5

linked tick species

State

geographic level

US-CO

location code

5 reviewed species records are currently linked to Colorado.

Introduced, occasional and other records

Adult female Amblyomma americanum lone star tick showing the central pale spot

Lone star tick

Amblyomma americanum

Rare Amblyomma hard_tick Colorado

Colorado State University Extension records the lone star tick as very rare, with possible occurrence in extreme eastern or southeastern Colorado.

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An aggressive human-biting hard tick widely distributed in the eastern United States and especially common in the South. Larvae, nymphs and adults bite people.

Identification:

The adult female has a single pale or white spot near the centre of the scutum. Adult males have pale markings around the posterior margin rather than one central spot. Mouthparts are relatively long.

Hosts: Humans, White-tailed deer, Small mammals, Birds, Dogs

Habitats: Woodland, Woodland edges and trails, Grassland and shrubland

Photographs and visible features may be insufficient for definitive identification.

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Magnified dorsal view of a Dermacentor albipictus winter tick larva

Winter tick

Dermacentor albipictus

Present Dermacentor hard_tick Colorado

Colorado State University Extension includes the winter tick among common ticks found in Colorado.

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A one-host Dermacentor species widely known as the winter tick. Human encounters are reported, while health claims require association-specific evidence.

Identification:

A hard tick in the genus Dermacentor. Species confirmation requires examination of diagnostic morphology; photographs, host and location alone may be insufficient.

Hosts: Humans, Horses

Photographs and visible features may be insufficient for definitive identification.

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Adult female Dermacentor andersoni on the left and adult male on the right with scutum differences marked

Rocky Mountain wood tick

Also known as: Rocky Mountain tick

Dermacentor andersoni

Present Dermacentor hard_tick Colorado

Colorado State University Extension identifies the Rocky Mountain wood tick as the most common tick species that bites people in Colorado.

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A hard tick of the Rocky Mountain states and southwestern Canada. Adults are the principal stage associated with pathogen transmission to humans.

Also known as: Rocky Mountain tick

Identification:

Adults are ornate Dermacentor ticks with short mouthparts, eyes and festoons. Females have a cream-patterned anterior scutum; males show pale mottling across most of the dorsum.

Hosts: Humans, Small mammals, Large mammals, Livestock, Dogs

Habitats: Rocky Mountain rangeland, Grassland and shrubland

Photographs and visible features may be insufficient for definitive identification.

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Adult male and female Dermacentor variabilis American dog ticks on a blade of grass

American dog tick

Also known as: Wood tick

Dermacentor variabilis

Present Dermacentor hard_tick Colorado

Colorado State University Extension records the American dog tick in Colorado, while noting it is uncommon and often associated with pet movement.

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A widespread North American hard tick. Adults commonly bite dogs and humans, while larvae and nymphs feed mainly on small mammals.

Also known as: Wood tick

Identification:

Adults have short mouthparts, eyes and festoons, with pale ornamentation on the dorsal shield. Females have a pale patterned scutum at the front; males have ornamentation across most of the dorsum.

Hosts: Humans, Dogs, Small mammals, Large mammals

Habitats: Woodland edges and trails, Grassland and shrubland

Photographs and visible features may be insufficient for definitive identification.

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Adult female and male Rhipicephalus sanguineus brown dog ticks in dorsal view

Brown dog tick

Rhipicephalus sanguineus

Present Colorado

Colorado State University Extension includes the brown dog tick among ticks found in Colorado.

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A globally distributed, dog-associated hard tick able to complete its life cycle in buildings and kennels. UK records are linked to importation; UKHSA reports no current evidence of establishment outdoors or as a resident UK population.

Identification:

Laterally produced angular basis capituli.

Eyes and festoons present.

Scutum lacks ornamentation.

Mouthparts relatively short compared with the basis capituli.

Coxa I has large paired internal and external spurs.

Rhipicephalus sanguineus is a species complex in some literature; expert morphological and sometimes molecular review may be necessary.

Photographs and visible features may be insufficient for definitive identification.

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Practical tick guidance

Related guidance

Use these VuxLore® resources alongside the location records and species profiles above.

Identify ticksSpecies, life stages and identification guidance Prevent and checkReduce exposure and perform thorough tick checks Remove ticksRemoval methods, tools and common problems Bites, symptoms and healthSourced guidance about bites, symptoms and disease

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