Reference Work Entry

The Prokaryotes

pp 529-546

The Genus Coxiella

  • Robert A. Heinzen
  • , James E. Samuel


Coxiella burnetii is a bacterial obligate intracellular parasite and the causative agent of human Q fever. The Australian physician Edward Derrick used the term “query (Q) fever” in 1935 to describe an outbreak of febrile illness of unknown etiology among abattoir workers in Queensland, Australia (Derrick, 1937). Although Derrick was successful in transmitting a febrile disease to guinea pigs using patient blood or urine, he was unsuccessful in visualizing or isolating the causative agent. Consequently, he sent infected guinea pig liver to Burnet and Freeman, who reproduced symptoms of the disease in various laboratory animals. Impression smears of spleen harvested from infected mice revealed large, intracellular vacuoles containing small rod-shaped organisms that resembled typical rickettsiae; consequently, the organism was named Rickettsia burnetii (Burnet and Freeman, 1937). Coincident with the Australian studies, a tick transmission study of Rocky Mountain s ...

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