Name: Haemophilus parainfluenzae Rivers 1922 (Approved Lists 1980)

Category: Species

Proposed as: sp. nov.

Etymology: pa.ra.in.flu.en’zae. Gr. prep. para, beside, alongside of, near, like; N.L. gen. fem. n. influenzae, specific epithet; N.L. gen. fem. n. parainfluenzae, resembling Haemophilus influenzae

Pronunciation (Latin), gender: ha͡e-MO-p^hi-lus pa-ra-in-flu-EN-za͡e, masculine

Type strain: ATCC 33392; CCUG 12836; CIP 102513; DSM 8978; NCTC 7857

See detailed strain information at

Conduct genome-based taxonomy at

16S rRNA gene: EU083530 Analyse FASTA

Effective publication: Rivers TM. Influenza-like bacilli: Growth of influenza-like bacilli on media containing only an autoclave-labile substance as an accessory food factor. Johns Hopkins Hospital Bulletin 1922; 33:429-431.

IJSEM list: Skerman VBD, McGowan V, Sneath PHA. Approved lists of bacterial names. Int J Syst Bacteriol 1980; 30:225-420.

Nomenclatural status: validly published under the ICNP

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

Risk group: 2

• Synonyms:

  • Name	Kind
    "Parahaemophilus parainfluenzae" (Rivers 1922) Segui et al. 2026	homotypic synonym, not validly published

• Notes:
  • 🧬 The phylogenomic assignment score of this taxon is 0.01985 (N = 33).
  • 😷 The risk group for Belgium has been imported on 2024-02-05. The full classification is: risk group = 2, note = "human pathogen". — The risk group for Canada has been imported on 2024-02-27. The full classification is: risk group = 2, note = "Animal classification RG: 2 - Security sensitive biological agent: No - Terrestrial animal pathogen under Canadian Food Inspection Agency authority: No - Containment level: Containment Level 2". — The risk group for Swiss Confederation has been imported on 2024-02-01. The full classification is: risk group = 2. — The risk group for Germany has been imported on 2026-08-13. The full classification is: risk group = 2. — The risk group for Taiwan has been imported on 2024-11-03. The full classification is: risk group = 2, note = "P650 = v". — 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 843 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. 🇬🇧

Parent taxon: Haemophilus corrig. Winslow et al. 1917 (Approved Lists 1980)

Assigned by: Rivers TM. Influenza-like bacilli: Growth of influenza-like bacilli on media containing only an autoclave-labile substance as an accessory food factor. Johns Hopkins Hospital Bulletin 1922; 33:429-431.

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Record number: 776647