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Volume 27, Number 6—June 2021

Etymologia: Enterocytozoon bieneusi

Maxime MoniotComments to Author , Philippe Poirier, and Céline Nourrisson
Author affiliation: Centre Hospitalier Universitaire, Clermont-Ferrand, France

Suggested citation for this article

Enterocytozoon bieneusi [′entərəˌsaitə′ӡu:ən bıə′nəʊsı]


Spores of Enterocytozoon bieneusi in a fecal smear from a patient with intestinal microsporidiosis. Spores are small (≈1.5 µm × 0.5 µm) and egg-shaped (calcofluor-white stain, original magnification ×1,000). Photograph courtesy of the corresponding author.

Figure. Spores of Enterocytozoon bieneusiin a fecal smear from a patient with intestinal microsporidiosis. Spores are small (≈1.5 µm × 0.5 µm) and egg-shaped (calcofluor-white stain, original magnification ×1,000)....

From the Greek énteron (intestine), kútos (vessel, cell), and zỗion (animal), and the surname Bieneus, in memory of the first infected patient whose case was reported in Haiti during 1985. Enterocytozoon bieneusi, a member of the wide-ranging phylum Microsporidia, is the only species of this genus known to infect humans. Microsporidia are unicellular intracellular parasites closely related to fungi, although the nature of the relationship is not clear (Figure).

E. bieneusi, a spore-forming, obligate intracellular eukaryote, was discovered during the HIV/AIDS pandemic and is the main species responsible for intestinal microsporidiosis, a lethal disease before widespread use of antiretroviral therapies. More than 500 genotypes are described, which are divided into different host-specific or zoonotic groups. This pathogen is an emerging issue in solid organ transplantation, especially in renal transplant recipients.



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  2. Didier  ES, Weiss  LM. Microsporidiosis: not just in AIDS patients. Curr Opin Infect Dis. 2011;24:4905. DOIPubMed
  3. Han  B, Weiss  LM. Microsporidia: obligate intracellular pathogens within the fungal kingdom. Microbiol Spectr. 2017;5:97113.PubMed
  4. Moniot  M, Nourrisson  C, Faure  C, Delbac  F, Favennec  L, Dalle  F, et al. Assessment of a multiplex PCR for the simultaneous diagnosis of intestinal cryptosporidiosis and microsporidiosis: epidemiologic report from a French prospective study. J Mol Diagn. 2021;23:41723. DOIPubMed




Suggested citation for this article: Moniot M, Poirier P, Nourrisson C. Etymologia: Enterocytozoon bieneusi. Emerg Infect Dis. 2021 Jun [date cited].

DOI: 10.3201/eid2706.et2706

Original Publication Date: April 29, 2021

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Table of Contents – Volume 27, Number 6—June 2021


Please use the form below to submit correspondence to the authors or contact them at the following address:

Maxime Moniot, Laboratoire de Parasitologie Mycologie, Centre Hospitalier Universitaire, 58 Rue Montalembert, Gabriel Montpied 63003, Clermont-Ferrand Cedex 1, France

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Page created: April 29, 2021
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