Noun
any of a group of very small rod-shaped bacteria that live in biting arthropods (as ticks and mites) and cause disease in vertebrate hosts; they cause typhus and other febrile diseases in human beings
Source: WordNetMedical uses It is first-line therapy for rocky mountain spotted fever (Rickettsia), Lyme disease (B. Source: Internet
In the periods between outbreaks, when human to human transmission occurs less often, the flying squirrel serves as a zoonotic reservoir for the Rickettsia prowazekii bacterium. Source: Internet