This could be a big year for ticks in Colorado. Here’s what you should know.

Key Points:

• Colorado is expecting a significant increase in tick activity in 2026 due to a mild winter and a wet spring in 2023, which created ideal conditions for ticks to survive and reproduce.
• The state primarily hosts American dog ticks and Rocky Mountain wood ticks, which can transmit diseases such as Colorado tick fever, Rocky Mountain spotted fever, tularemia, tick-borne relapsing fever, and tick paralysis, though these illnesses remain rare.
• Lyme disease, transmitted by deer ticks, is not established in Colorado but is the most reported tick-borne illness among residents due to travel to other states where the disease is prevalent.
• Alpha-gal syndrome, an allergy to red meat triggered by tick bites (primarily from lone star ticks not yet common in Colorado), is a growing concern as the lone star tick expands its range toward the state’s eastern border.
• Preventative measures include using EPA-registered insect repellents, treating clothing with permethrin, conducting thorough tick checks after outdoor activities, and participating in Colorado’s tick surveillance program by submitting found ticks for identification.