Diagnostic Findings [Last Modified: ]
Microsporidiosis
[Anncaliia spp.] [Encephalitozoon cuniculi] [Encephalitozoon hellem] [Encephalitozoon intestinalis (syn. Septata intestinalis)] [Tubulinosema acridophagus]
[Enterocytozoon bieneusi] [Nosema spp.] [Pleistophora sp.] [Trachipleistophora spp.] [Vittaforma corneae (syn. Nosema corneum)]
Causal Agent Life Cycle Geographic Distribution Clinical Features Laboratory Diagnosis Treatment

Light microscopy
Different staining techniques can be used to demonstrate microsporidian spores in clinical specimens.

The spores appear as oval to round shaped structures, measuring 1 to 4 µm (depending on the species).  Some stains (Gram Chromotrope [A, B], and Chromotrope 2R [C]) highlight a belt-like stripe in the equatorial diameter of the spores.

Encephalitozoon cuniculi stained with Gram Chromotrope Encephalitozoon cuniculi stained with Gram Chromotrope
A B

A:  Stool smear stained with Gram Chromotrope containing Encephalitozoon cuniculi spores.

Microsporidia in stool stained with Chromotrope 2R
C

C: Stool smear stained with Chromotrope 2R containing spores of an unidentified microsporidian.

microsporidia stained with Giemsa microsporidia stained with Giemsa
D E

D, E: Spores of an unidentified microsporidian species stained with Giemsa. These images were taken from corneal sections. The spore in Figure E has its polar tubule extruded. Images courtesy of the Swedish Institute of Communicable Diseases Control, Solna, Sweden.

Encephalitozoon cuniculi stained with Ryan's modified trichrome Encephalitozoon cuniculi stained with Ryan's modified trichrome
F G

F, G: Spores of Encephalitozoon cuniculi stained with Ryan's modified trichrome (trichrome blue). The specimen in Figure F is from a kidney biopsy; the specimen in Figure G is from urine of the same patient. Images courtesy of the Mayo Clinic, Rochester, MN.
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