Female western black-legged tick, Ixodes pacificus, can transmit Borrelia burgdorferi, the bacteria that causes Lyme disease. These ticks are mainly found in western Washington and live in forested or brushy areas.

Photo: James Gathany, CDC

The first sign of Lyme disease is usually an expanding cicular rash which starts at the site of the tick bite. This rash, called erythema migrans, occurs in most Lyme disease patients and often, but not always, 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: James Gathany, CDC

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, Vector-Borne Disease Section, Used with permission.

These are three western black-legged ticks, Ixodes pacificus. 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 a creamy or light tan color. The bottom left tick is an unfed female. The tick on the bottom right is an unfed male.

Photo: California Department of Public Health, Vector-Borne Disease Section, Used with permission.

Female American dog tick, Dermacentor variabilis, live throughout the state and prefer woodland areas, medium height grasses and shrubs between wetlands and woods, and sunny or open areas around woods.

Photo: James Gathany, CDC

Female Rocky Mountain wood tick, Dermacentor andersoni. The life cycle of this tick may require up to 2 to 3 years for completion. Adult wood ticks feed primarily on large mammals, while the larvae and nymphs feed on small rodents. These ticks are found throughout the state but prefer woodland areas, medium height grasses and shrubs between wetlands and woods, and sunny or open areas along the edge of woods.

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 throughout the state but prefer woodland areas, medium height grasses and shrubs between wetlands and woods, and sunny or open areas along the edge of woods.

Photo: James Gathany, CDC