Ticks are present in Colorado, and residents or visitors engaging in outdoor activities should be aware of the species found in the state. Several species thrive in the diverse Colorado environment. Understanding which ticks are active, where they live, and the potential health concerns they carry allows for proper precautions, especially during the warmer months when tick activity peaks.
Confirmation and Common Species in Colorado
The most frequently encountered species in Colorado is the Rocky Mountain Wood Tick, scientifically known as Dermacentor andersoni. This tick is a hard-bodied variety with a reddish-brown, teardrop-shaped body when unfed. Adult females are distinguishable by a white or silver-gray shield, while males feature gray and white spots across their backs. Another common species is the American Dog Tick, Dermacentor variabilis, which is dark brown, and the adult female has a large off-white scutum or shield. The primary vector for Lyme disease, the Blacklegged Tick (Ixodes scapularis), is not established in Colorado.
Geographic Distribution and Habitat
Ticks in Colorado are found in transitional areas, such as scrublands, grasslands, and lightly wooded foothills. The Rocky Mountain Wood Tick is active in mountainous regions, often at elevations ranging from 4,000 to 10,000 feet above sea level. Conversely, the American Dog Tick is more prevalent in the state’s eastern plains. Tick activity is highly seasonal, with adults becoming active as early as March and peaking in the late spring and early summer (late April through mid-July). Activity decreases during the hottest, driest parts of mid-summer.
Health Risks Specific to Colorado Ticks
The most common tick-transmitted illness in Colorado is Colorado Tick Fever (CTF), a viral infection carried almost exclusively by the Rocky Mountain Wood Tick (D. andersoni). Symptoms of CTF, which can appear one to 14 days after a bite, often include fever, chills, headache, and body aches. About half of patients experience a characteristic biphasic fever, where a fever resolves only to return for a second period of illness. There is no specific treatment for this virus, so care focuses on managing the symptoms. Rocky Mountain Spotted Fever (RMSF), despite its name, is rare in Colorado, with only a few cases reported each year. This bacterial disease, caused by Rickettsia rickettsii, can be transmitted by the Rocky Mountain Wood Tick, American Dog Tick, and Brown Dog Tick. RMSF can progress rapidly and is treated with antibiotics, making early recognition of symptoms, such as fever and headache, important.
Prevention and Safe Removal Techniques
Effective prevention begins with dressing appropriately when entering tick habitats.
- Wear light-colored clothing to make ticks easier to spot.
- Tuck pants into socks and wear long sleeves to block ticks from reaching the skin.
- Apply insect repellents containing DEET, picaridin, or IR3535 to exposed skin.
- Treat clothing with permethrin for lasting defense.
After spending time outdoors, conduct a thorough tick check on yourself, children, and pets. If a tick is found attached, remove it promptly using fine-tipped tweezers. Grasp the tick close to the skin’s surface and pull upward with steady pressure, avoiding twisting or jerking motions. Clean the bite area and your hands thoroughly with rubbing alcohol or soap and water once the tick is removed.