Western Black-legged Tick
Photo: James Gathany, CDC
Female western black-legged tick, Ixodes pacificus, can transmit Borrelia burgdorferi, the bacteria that causes Lyme disease. It can also transmit the pathogen that causes anaplasmosis in dogs. These ticks are mainly found in Western Washington as well as along the eastern slopes of the Cascade Mountains. They live in forested or brushy areas. See CDC's maps of where Ixodes pacificus has been found.
Photos: James Gathany, CDC and Anna Perez, CDC
The first sign of Lyme disease is usually an expanding circular rash which starts at the site of the tick bite. This rash, called erythema migrans, occurs in most Lyme disease patients. Often, but not always, the rash has a “bull's-eye” appearance. Lyme disease is caused by the bacterium Borrelia burgdorferi, and is transmitted by the bite of infected black-legged ticks.
Photo: California Department of Public Health
Western black-legged ticks, Ixodes pacificus, on a finger. From left to right: nymph, adult male, and adult female.
Photo: California Department of Public Health
Three western blacklegged ticks, Ixodes pacificus, on a ruler. The tick on the top is a fed, or engorged, female. A tick's body slowly enlarges to accommodate the amount of blood ingested. Engorged ticks that are still attached and feeding often have either a gray or light tan color. The bottom left tick is an unfed female. The tick on the bottom right is an unfed male.
Western Dog Tick
Photo: James Gathany, CDC
Female western dog tick, Dermacentor similis, live primarily in eastern and parts of southwest Washington. They prefer woodland areas, medium height grasses and shrubs between wetlands and woods, and sunny or open areas around woods. Adult western dog ticks are common pests of dogs while larvae. The nymphs prefer feeding on small mammals like rodents.
Rocky Mountain Wood Tick
Photo: James Gathany, CDC
Female Rocky Mountain wood tick, Dermacentor andersoni. The life cycle of this tick may require up to two to three years for completion. Adult wood ticks feed primarily on large mammals, while the larvae and nymphs feed on small rodents. These ticks are found primarily on the eastern side of the state. They prefer woodland areas, medium height grasses and shrubs between wetlands and woods, and sunny or open areas along the edge of woods. Rocky Mountain wood ticks and western dog ticks look very similar to each other.
Photo: James Gathany, CDC
Male Rocky Mountain wood tick, Dermacentor andersoni. Adult wood ticks feed primarily on large mammals, while the larvae and nymphs feed on small rodents. These ticks are found primarily on the eastern side of the state. They prefer woodland areas, medium height grasses and shrubs between wetlands and woods, and sunny or open areas along the edge of woods.
Soft Tick
Photo: Anna Perez, CDC
Soft ticks, Ornithodoros hermsi, is the vector for tick-borne relapsing fever. Tick-borne relapsing fever is usually linked to sleeping in rustic, rodent-infested cabins in mountainous areas. Because soft ticks usually feed at night and remain attached for a very short time, most people never realize a tick bit them.