Species Orientia tsutsugamushi

Name: Orientia tsutsugamushi (Hayashi 1920) Tamura et al. 1995

Category, proposed as: species, comb. nov.

Basonym: "Theileria tsutsugamushi" Hayashi 1920

Etymology: tsut.su.ga.mu’shi. from N.L. gen. neut. n. tsutsugamushi, popular name of the disease caused by this species, generally interpreted to mean "mite disease" (from two Japanese ideographs transliterated tsutuga something small and dangerous, and mushi a creature, now known to be a mite) [probably better: tsutsugamushii]

Pronunciation (Latin), gender: o-ri-EN-ti-a tsut-su-ga-MU-s͡hi, feminine

Type strain: ATCC VR-150; Karp

Conduct genome-based taxonomy at

16S rRNA gene: D38623 Analyse FASTA

Valid publication: Tamura A, Ohashi N, Urakami H, Miyamura S. Classification of Rickettsia tsutsugamushi in a new genus, Orientia gen. nov., as Orientia tsutsugamushi comb. nov. Int J Syst Bacteriol 1995; 45:589-591.

IJSEM list: Anonymous. Notification list. Notification that new names and new combinations have appeared in volume 45, part 3 of the IJSB. Int J Syst Bacteriol 1995; 45:881.

Nomenclatural status: validly published under the ICNP

Taxonomic status: correct name (and explicitly recommended for medical use)

Risk group: 3

• Synonyms:

  • Name	Kind
    "Theileria tsutsugamushi" Hayashi 1920	homotypic synonym, not validly published, basonym of name in Approved Lists
    Rickettsia tsutsugamushi (Hayashi 1920) Ogata 1931 (Approved Lists 1980)	homotypic synonym, validly published under the ICNP

• Emendations:
  • Hördt et al. 2020 Hordt A, Lopez MG, Meier-Kolthoff JP, Schleuning M, Weinhold LM, Tindall BJ, Gronow S, Kyrpides NC, Woyke T, Goker M. Analysis of 1,000+ Type-Strain Genomes Substantially Improves Taxonomic Classification of Alphaproteobacteria. Front Microbiol 2020; 11:468. 🇩🇪 Oren A, Garrity GM. List of changes in taxonomic opinion no. 32. Notification of changes in taxonomic opinion previously published outside the IJSEM. Int J Syst Evol Microbiol 2020; 70:4061-4090.

• Notes:
  • 🥇 Nomenclatural type of the genus Orientia Tamura et al. 1995. Publication: Tamura A, Ohashi N, Urakami H, Miyamura S. Classification of Rickettsia tsutsugamushi in a new genus, Orientia gen. nov., as Orientia tsutsugamushi comb. nov. Int J Syst Bacteriol 1995; 45:589-591.
  • 😷 The risk group for Belgium has been imported on 2024-02-05. The full classification is: risk group = 3, note = "human and animal pathogen - biological class of risk animal: 3". — The risk group for Canada has been imported on 2024-02-27. The full classification is: risk group = 3, note = "Animal classification RG: 2 - Security sensitive biological agent: No - Terrestrial animal pathogen under Canadian Food Inspection Agency authority: No - Containment level: Containment Level 3". — The risk group for Swiss Confederation has been imported on 2024-02-01. The full classification is: risk group = 3. — The risk group for Germany has been imported on 2026-08-13. The full classification is: risk group = 3, note = "Z". — The risk group for France has been imported on 2024-08-30. The full classification is: risk group = 3. — The risk group for United Kingdom has been imported on 2024-01-31. The full classification is: risk group = 3. — The risk group for United States has been imported on 2024-02-09. The full classification is: risk group = 3. — If in doubt, use the risk group given in the regulations for your country and, if these are not available, use the risk group given in the catalogue of the culture collection from which you have obtained or intend to obtain the strain.
  • 🎓 Name mentioned 1375 times in PubMed until 2026-06-11.
  • 🙆 This name is on the List of Recommended Names for bacteria of medical importance (LoRN) as the name to be applied to this species. The name is on LoRN because of the recorded risk group of the species itself.
  • 🧍 According to Bartlett et al. (2022), this species is an established human pathogen. Publication: Bartlett A, Padfield D, Lear L, Bendall R, Vos M. A comprehensive list of bacterial pathogens infecting humans. Microbiology (Reading) 2022; 168:0. 🇬🇧
  • 🧍 In the paper by Tamura et al. 1995, the type strain is erroneously cited as ATCC VR 150 (without dash). — Tang J. Personal communication, 2001-05-30.

Parent taxon: Orientia Tamura et al. 1995

Assigned by: Tamura A, Ohashi N, Urakami H, Miyamura S. Classification of Rickettsia tsutsugamushi in a new genus, Orientia gen. nov., as Orientia tsutsugamushi comb. nov. Int J Syst Bacteriol 1995; 45:589-591.

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Record number: 784544