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Related to rickettsiae: bacteria, viruses, Chlamydiæ, chlamydiae, Spirochetes


n. pl. rick·ett·si·ae (-sē-ē′)
Any of various bacteria of the genus Rickettsia, carried as parasites by many ticks, fleas, and lice, that cause diseases such as typhus and Rocky Mountain spotted fever in humans.

[New Latin Rickettsia, genus name, after Howard Taylor Ricketts (1871-1910), American pathologist.]

rick·ett′si·al adj.


n, pl -siae (-sɪˌiː) or -sias
(Microbiology) any of a group of parasitic bacteria that live in the tissues of ticks, mites, and other arthropods, and cause disease when transmitted to man and other animals
[C20: named after Howard T. Ricketts (1871–1910), US pathologist]
rickˈettsial adj


(rɪˈkɛt si ə)

n., pl. -si•as, -si•ae (-siˌi)
any of various rod-shaped infectious microorganisms of the heterogeneous group Rickettsieae, formerly classified with the bacteria but markedly smaller and reproducing only inside a living cell: parasitic in fleas, ticks, mites, or lice and transmitted by bite.
[< New Latin (1916), after Howard T. Ricketts (1871–1910), U.S. pathologist; see -ia]
rick•ett′si•al, adj.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.rickettsia - any of a group of very small rod-shaped bacteria that live in biting arthropods (as ticks and mites) and cause disease in vertebrate hosts; they cause typhus and other febrile diseases in human beings
eubacteria, eubacterium, true bacteria - a large group of bacteria having rigid cell walls; motile types have flagella
family Rickettsiaceae, Rickettsiaceae - microorganism resembling bacteria inhabiting arthropod tissues but capable of causing disease in vertebrates


n. ricketsia, rickettsia, uno de los organismos gram-negativos que se reproducen solamente en células huéspedes de pulgas, piojos, garrapatas y ratones, y que se transmiten a humanos a través de las mordidas de éstos.
References in periodicals archive ?
After he recovered, Weigl inoculated, successfully, rickettsiae from the lice that had fed on him to other lice.
of Arizona College of Medicine) and practitioner Friedman, along with a host of contributors, address a broad spectrum of viruses, bacteria, fungi, rickettsiae, spirochetes, microbacteria and parasites as well as cat-scratch disease and HIV.
Louse-borne typhus is no longer the major public health problem it once was in South Africa, (1) and in southern Africa rickettsiae are now best known as agents of tick bite fever (TBF); although Coxiella burnetii, the cause of Q fever, is also widespread in the region, it is far less often identified as a cause of human disease.
Rickettsiae are gram-negative coccobacillary bacteria that are strict intracellular parasites.
In the United States, infections with rickettsiae are known to cause diseases such as Rocky Mountain spotted fever, rickettsialpox and murine typhus.
Spotted fever group rickettsiae in ticks and fleas from the Democratic Republic of the Congo.
International Conference on Rickettsiae and Rickettsial Diseases (4th: 2005: Logrono, Spain).
This new genetic information on the rickettsiae, combined with that obtained by the Human Genome Project, will help us to understand the causes of the cellular injury that occur during infection.
To the Editor: Rickettsia felis, which belongs to the spotted fever group of rickettsiae, causes febrile illness in humans.
Other original research papers in the premier issue focus on tick-borne infections including spotted fever rickettsiae and on other new Lyme disease field and laboratory experiments.
To the Editor: Infections with typhus group rickettsiae (TGR), spotted fever group rickettsiae (SFGR), and scrub typhus group orientiae (STGO) have been reported among persons in South Korea in increasing numbers over the past decade (1,2).
The 15 ticks were defrosted, surface sterilized with iodine alcohol, and processed individually by the shell vial technique for isolation of rickettsiae in Vero cells, as described (6).