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.
{{center|Genus II. Coxiella Philip, (1943) 1948.
{{c|(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
