Adult: The adult louse is about the size of a sesame seed, has six legs, and is tan to grayish-white. In persons with dark hair, the adult louse will look darker. Females lay nits; they are usually larger than males. Adult lice can live up to 30 days on a person's head.
The four tick-borne diseases are 1) borreliosis (including Lyme disease and related conditions), 2) Rocky Mountain spotted fever, 3) ehrlichiosis, and 4) tularemia, which is also known as rabbit fever.
1 Borrelia miyamotoi infection has recently been described as a cause of illness in the U.S. It is transmitted by the blacklegged tick (Ixodes scapularis) and has a range similar to that of Lyme disease.2  Colorado tick fever is caused by a virus transmitted by the Rocky Mountain wood tick (Dermacentor andersoni). Lyme disease is transmitted by the blacklegged tick (Ixodes scapularis) in the northeastern U.S. and upper midwestern U.S. and the western blacklegged tick (Ixodes pacificus) along the Pacific coast. 2  Powassan disease is transmitted by the blacklegged tick (Ixodes scapularis) and the groundhog tick (Ixodes cookei).