(n)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
(n)mild infectious rickettsial disease caused by a bacterium of the genus Rickettsia transmitted to humans by the bite a mite that lives on rodents; characterized by chills and fever and headache and skin lesions that resemble chickenpox