FAMILY I. RICKETTSIACEAE 



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1) Dermacentroxenus sibericus Zdrodovskiy 

 (Zhur. Mikrobiol., Epidemiol., Immuno- 

 bioL, No. 10, 1949, 19; in Zhdanov and 

 Korenblit, ibid., 1950, 42, and later articles, 

 Dermacentroxenus is reduced to a subgenus 

 under Rickettsia) , which is probably related 

 to R. conorii, was proposed for the tick- 

 borne agent of Siberian tick typhus; rick- 

 ettsial relationships and an account of the 



former are most recently provided by Zdro- 

 dovskiy and Golinevitch (Treatise on 

 Rickettsia and Rickettsiosis, Medgiz, Mos- 

 cow, 1956, 82-168); 2) Rickettsia pavlovskii 

 Korshunova (in Pavlovsky et al., Nat. Nidi 

 Hum. Dis. and Regional Epidemiol., Med- 

 giz, Moscow, 1955, 242) was more recently 

 proposed for a disease agent carried by 

 ticks, mites and fleas. 



Genus II. Coxiella Philip, (1943) 1948. 



(Subgenus Coxiella Philip, Amer. Jour. Hyg., 37, 1943, 306; Burnetia Macchiavello, Prim. 



Reunion Interamer. del Tifo, Mexico, 1947, 408; subgenus Dyera Macchiavello, loc. cit.; 



see Philip, Ann. New York Acad. Sci., 56, 1953, 490; Coxiella Philip, U. S. Public 



Health Rep., 63, 1948 (January 9), 58 (incorrectly attributed to Bengson, in 



Manual, 6th ed., 1948 (January 26), 1092); Cexiella (sic) Zhdanov and 



Korenblit, Jour. Microbiol., Epidemiol, and Immunobiol. (Russian), 



No. 9, 1950, 42.) 



Co.xi.el'la. M.L. fern. dim. ending -ella; M.L. fem.dim.n. Coxiella named for Herald R. 



Cox, who was a codiscoverer of the agent of Q fever in America. 



Small, pleomorphic, rod-shaped or coccoid organisms occurring intracellularly in the 

 cytoplasm of infected cells and possibly extracellularly in infected ticks. Filterable. Stain 

 lightly with aniline dyes. Gram-negative. Have not been cultivated in cell-free media. 

 Parasites of man and other animals. Includes the etiological agent of Q fever. Produces no 

 typhus-like rash or Weil-Felix titer in man. Not dependent on arthropod transmission in 

 the infectious cycle. 

 The type species is Coxiella burnetii (Derrick) Philip. 



1. Coxiella burnetii (Derrick, 1939) 

 Philip, (1943) 1948. {Rickettsia burneti (sic) 

 Derrick, Med. Jour. Australia, 1, 1939, 14; 

 Rickettsia diaporica Cox, U. S. Pub. Health 

 Rep., 64, 1939, 1826; Rickettsia burneti var. 

 americana Anonymous, Brit. Med. Jour., 

 2, 1941, 588; Rickettsia (Coxiella) burneti 

 (sic) Philip, Amer. Jour. Hyg., 37, 1943, 

 306; Burnetia (Dyera) burneti Macchiavello, 

 Prim. Reunion Interamer. del Tifo, Mexico, 

 1947, 409; Burnetia (Dyera) burneti var. 

 diaporica Macchiavello, loc. cit.; Coxiella 

 burneti (sic) Philip, U. S. Pub. Health 

 Rep., 63, 1948, 58; Rickettsia burneti var. 

 caprina Caminopetros, Ann. Inst. Past., 77 , 

 1949, 750; Cexiella (sic) diaporica Zhda- 

 nov and Korenblit, Jour. Microbiol., Epi- 

 demiol, and Immunobiol. (Russian), No. 

 9, 1950, 42; Rickettsia burneti var. henzerling 

 Kausche and Sheris, Ztschr. f. Hyg., 133, 

 1951, 158.) 



bur.ne'ti.i. M.L. gen.noun burnetii of 

 Burnet; named for F. M. Burnet, who first 

 studied the agent causing Q fever in Aus- 

 tralia. 



Small, bacterium-like, pleomorphic or- 

 ganisms varying in size from coccoid forms 

 to well-marked rods. Occur as intracellular 

 micro-colonies with diffuse or compact dis- 

 tribution of the organisms through the cyto- 

 plasm. Also seen extracellularly, where they 

 appear as small, lanceolate rods, diplobacilli 

 and occasionally segmented filamentous 

 forms. Chains of 3 to 6 elements often seen. 

 Quite uniform in size and morphology in 

 infected yolk sacs and in mouse spleen with 

 exceedingly minute forms in heavily in- 

 fected material. Small lanceolate rods, 0.25 

 by 0.4 to 0.5 micron, bipolar forms 0.25 

 by 1.0 micron, diplobacilli 0.25 by 1.5 mi- 

 crons. Non-motile. Under the electron 

 microscope, organisms from yolk-sac 

 sources average 0.32 by 0.73 micron with 

 closer-fitting envelopes over a more regular 

 internal organization than that of Rickettsia 

 prowazekii. With Giemsa's stain the cells 

 appear reddish purple; with Macchiavello's 

 stain, bright red against a blue background. 

 Gram-negative. 



Cultivation: May be cultivated in plasma 



