RICKETTSIA

noun (plural -sias or ~e; also -sia) Etymology: New Latin, genus name, from Howard T. Ricketts died 1910 American pathologist Date: 1919 any of a family (Rickettsiaceae) of rod-shaped, coccoid, or diplococcus-shaped, often pleomorphic gram-negative bacteria that are intracellular parasites of arthropods (as lice or ticks) and when transmitted to humans cause various diseases (as typhus), ~l adjective