Lyme disease is a concern, prompting questions about its presence in various regions, including Colorado. This bacterial infection, transmitted through tick bites, can lead to a range of symptoms if left untreated. Understanding the specific risks and prevalence in Colorado is important for residents and visitors.
Understanding Lyme Disease in Colorado
While some Colorado residents may receive a Lyme disease diagnosis, these cases are rarely contracted within the state’s borders. Colorado is not considered endemic for Lyme disease because the primary tick species responsible for transmitting the illness, Ixodes scapularis (blacklegged tick) and Ixodes pacificus (western blacklegged tick), are not established in the state. The vast majority of Lyme disease cases reported in Colorado residents are associated with travel to endemic regions, such as the northeastern or upper midwestern United States.
Lyme disease is caused by the bacterium Borrelia burgdorferi, transmitted through the bite of an infected blacklegged tick. Early symptoms include fever, chills, headache, fatigue, and muscle aches. A characteristic “bull’s-eye” rash, known as erythema migrans, develops in approximately 70% to 80% of infected individuals, appearing 3 to 30 days after a tick bite. While other Ixodes tick species that can carry Lyme bacteria have been reported in Colorado, they pose a low risk for human transmission due to their specific behaviors and habitats.
Colorado’s Tick Landscape
Colorado is home to several tick species, though those capable of transmitting Lyme disease are largely absent. Common ticks in the state include the Rocky Mountain wood tick (Dermacentor andersoni), the American dog tick (Dermacentor variabilis), and the brown dog tick (Rhipicephalus sanguineus). These tick species are found in grassy areas, shrublands, and lightly wooded environments, often at subalpine elevations. Tick activity in Colorado peaks during the spring and early summer months, but ticks can remain active throughout the year.
While these Colorado ticks do not transmit Lyme disease, they can carry other pathogens causing different tick-borne illnesses. Colorado tick fever is the most common tick-borne disease in Colorado, a viral infection transmitted by the Rocky Mountain wood tick, causing flu-like symptoms. Other diseases found in the state include Rocky Mountain spotted fever, tularemia, and tick-borne relapsing fever. The bite of certain ticks, particularly the Rocky Mountain wood tick, can lead to tick paralysis, a temporary condition characterized by ascending weakness that resolves upon tick removal.
Protecting Yourself from Tick-Borne Illnesses
Taking precautions can reduce the risk of tick bites and subsequent illness when enjoying Colorado’s outdoors. Wearing appropriate clothing, such as long-sleeved shirts and long pants, minimizes skin exposure to ticks. Tucking pant legs into socks or boots creates a barrier, and choosing light-colored clothing makes it easier to spot ticks. Using EPA-registered insect repellents containing active ingredients like DEET, picaridin, or IR3535 on exposed skin and clothing provides protection.
After spending time outdoors, perform thorough tick checks on yourself, children, and pets. Pay close attention to areas such as the scalp, behind the ears, in and around hair, armpits, inside the belly button, behind the knees, waist, and groin.
If a tick is found attached, remove it promptly with fine-tipped tweezers. Grasp the tick as close to the skin’s surface as possible and pull upward with steady, even pressure, avoiding twisting or jerking movements that could leave parts of the tick embedded. Clean the bite area and your hands with rubbing alcohol or soap and water after removal. If symptoms such as fever, rash, or body aches develop after a tick bite, seek medical attention.