The risk of encountering ticks and tick-borne diseases in Washington State is generally lower than in the Northeast or Upper Midwest regions of the United States. While the state is home to several tick species capable of transmitting pathogens, locally acquired human illness is considered rare statewide. However, the presence of these parasites is widespread, and localized risks exist across different geographical areas for residents and visitors engaging in outdoor activities. The specific danger depends heavily on which side of the Cascade Mountains one is recreating and the particular species of tick involved.
Identifying the Primary Ticks and Geographical Risk Zones
Washington State hosts four main tick species that occasionally bite humans, with their distribution largely divided by the Cascade mountain range. The Western Blacklegged Tick is the primary species of concern west of the Cascades. It prefers the moist, brushy, and forested habitats of Western Washington and the eastern slopes of the mountains. This tick is active primarily during the milder, wetter periods from late fall through early spring.
In contrast, the drier, more open environments of Eastern Washington are home to the Rocky Mountain Wood Tick and the Western Dog Tick. These species favor grasslands, open woodlands, and shrub-steppe areas, with their activity peaking in the spring and early summer months. A fourth species, the soft tick, is less frequently encountered but is found in mountainous regions, often associated with rustic cabins or rodent-infested areas. The soft tick typically feeds quickly and painlessly at night.
The geographical separation of these species means the risk profile changes significantly depending on location. The Western Blacklegged Tick carries the bacteria responsible for Lyme disease and Anaplasmosis in Western Washington. The Rocky Mountain Wood Tick and Western Dog Tick in Eastern Washington are vectors for Rocky Mountain Spotted Fever, Tularemia, and can cause Tick Paralysis.
Documented Tick-Borne Illnesses in Washington State
While ticks are present across Washington, confirmed cases of locally acquired tick-borne illness remain uncommon compared to national averages. Lyme disease, the most reported tick-borne illness nationally, sees only a small number of cases confirmed as acquired within the state each year. The majority of Lyme cases reported among Washington residents are travel-associated, contracted in states with higher endemic rates.
Several other diseases are confirmed to be transmitted by ticks within the state. Rocky Mountain Spotted Fever (RMSF) is a bacterial disease carried by the Rocky Mountain Wood Tick and Western Dog Tick, though reported human cases in Washington are rare. Symptoms of RMSF often begin with a sudden high fever and severe headache.
Tick-Borne Relapsing Fever (TBRF) and Tularemia are among the most frequently reported locally acquired tick-borne diseases in Washington. TBRF is transmitted by soft ticks, and its hallmark is a cycling pattern of high fever, headaches, and joint aches that can recur for weeks if untreated. Anaplasmosis, transmitted by the Western Blacklegged Tick, causes non-specific flu-like symptoms. It has been identified in the local tick population, with the first likely locally acquired human case reported in 2022.
Essential Prevention and Safe Removal Techniques
The most effective strategy against tick-borne illness involves preventing the bite, especially when hiking or spending time in grassy or wooded areas. Wearing long-sleeved shirts and long pants tucked into socks creates a barrier, keeping ticks on the outer layer of clothing where they are easier to spot. Light-colored clothing is recommended because it makes the small, dark ticks more visible against the fabric.
Applying an insect repellent containing at least 20% DEET, picaridin, or oil of lemon eucalyptus to exposed skin and clothing provides protection. When walking on trails, staying in the center of the path and avoiding contact with tall grass and brush reduces the opportunity for ticks to latch onto a host. Since ticks often require many hours of attachment to transmit disease, performing a thorough body check immediately after coming indoors is a necessary prevention step.
If a tick is found attached, prompt and correct removal is necessary to minimize the risk of infection. Use fine-tipped tweezers to grasp the tick as close to the skin’s surface as possible, near the head or mouthparts. Pull upward with a steady, even pressure, avoiding twisting or jerking the tick, which could cause the mouthparts to break off. After removal, the bite area and hands should be cleaned thoroughly with rubbing alcohol or soap and water.
The removed tick should be disposed of by flushing it down the toilet or placing it in a sealed container with alcohol. Avoid using folklore remedies like petroleum jelly, heat, or nail polish, as these methods can irritate the tick and cause it to release more fluids into the bite site. If a rash develops, or if flu-like symptoms occur within several weeks of the bite, a healthcare provider should be consulted immediately and informed of the history of the tick bite.