A genus of widely distributed parasitic ticks. Several species are responsible for transmitting the diseases tularemia, Rocky Mountain spotted fever, and Russian spring-summer encephalitis. The bite of a few species can give rise to a serious paralysis, caused by a toxin in the tick’s saliva.
A classification of parasitic arachnids known for transporting the bacterium Borrelia burgdorferi and introducing it into the host organism during the blood-feeding process.