Rickettsia

A genus of small, rod-shaped, round to pleomorphic microorganisms in the order Rickettsiales. They are true bacteria, gram-negative, and cultivable only in living tissues. Transmitted by lice and ticks, they cause disease in humans and domestic animals but are also found in the cytoplasm of tissue cells of lice, fleas, ticks and mites, which may act as reservoirs and vectors. See also ehrlichia and coxiella.

• R. akari — causes rickettsial pox in humans, mice and rats.
• R. australis — causes queensland tick typhus in humans, small marsupials, rats.
• R. canadensis — causes new typhus in humans and rabbits.
• R. conjunctivae — see Chlamydophila pecorum.
• R. conorii — causes boutonneuse fever in humans and dogs and small feral mammals.
• R. ovina — see Ehrlichia ovina.
• R. phagocytophila — see Anaplasma phagocytophila.
• R. prowazeki — causes epidemic typhus in humans and possibly cattle, sheep and goats.
• R. rickettsii — causes spotted fever in humans and many feral animals, especially rodents and in dogs and birds. See also rocky mountain spotted fever.
• R. ruminantium — see Ehrlichia ruminantium.
• R. rupricaprae — see Mycoplasma conjunctivae.
• R. sibirica — causes Siberian tick typhus in humans and many feral mammals, especially rodents.
• R. tsutsugamushi — see Orientia tsutsugamushi.
• R. typhi — causes murine typhus in humans and the brown rat.