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I. Detection of Cryptosporidium, Cyclospora, and Cystoisospora in stool specimens

Nimit Morakote

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Review

Diarrheic stool specimens

Oocysts of coccidia

Cryptosporidium parvum

Cystoisospora belli, and

Cyclospora cayetanensis

Spores of microsporidia

Enterocytozoon bieneusi

Encephalitozoon intestinalis

Others, e.g., Giardia, Capillaria

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Stool examination for oocysts

Wet mount- difficult to identify

(colorless)

Stain- easy to identify

Acid fast stain for oocyst

Modified Ziehl-Neelsen acid fast

Or other kinds

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I. belli

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C. parvum

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C. cayetanensis

Ortega YR, Gilman RH, Sterling CR. A new coccidian parasite (Apicomplexa:Eimeriidae) from humans. J Parasitol 1994;80(4):625-9.

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Sporulation

Used to confirm species of Cyclospora

First, concentrate oocysts by sugar floatation

(Sheather’s sucrose)

This step can be omitted if numerous oocysts are

present

Wash in water and resuspend in 2% sulfuric acid

or 2.5%K-dichromate.

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8 http://www.ksu.edu/parasitology/cyclospora/nomarski

C. cayetanesis sporulation

7-12 days at 30 C

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Detection of microsporidium in faeces

Enterocytozoon bieneusi, and

Encephalitozoon intestinalis

Spores, 1.0x1.5 to 2.0x4.0 micrometer

Modified trichrome for light microscopy

(5X Chromotrope 2R)

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Morphology

Pink spore with

transverse band

(“belt”)

Didier ES et al. J Clin Microbiol

1995;33(12):3138-45.

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Conclusion Part I

Diarrheic stool

Acid fast stain for

Cryptosporidium, Isospora and

Cyclospora

modified Trichrome stain for

microsporidium

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II. Examination of tissues for diagnosis of some parasitosis

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Trichinosis

Infection by eating raw or inadequatedly

cook meat

Hilltribe pig, wild boar, wild animals

Symptoms may start as early as 48 hours

Mostly come 2 wk after infection with

myalgia, periorbital edema, facial edema

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Trichinosis (cont.)

Muscle biopsy

Patho lab- section and stain

Compression method

good for infection>3wk.

T.papuae, T. pseudospiralis-

no capsule

Not sensitive

If negative- serological

diagnosis

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Toxoplasmosis

Parasites in brain, heart and other

tissues

Tissue specimens

Blood

Lymh node biopsy

Primarily diagnosed by serology

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Toxoplasmosis (cont.)

Ground tissues

Mouse inoculation, ip.

5-6 days-Peritoneal fluid (tachyzoites)

1 mo.-Brain (cysts)

Blood- antibodies

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Toxoplasma

Tachyzoite-Wet

mount

Tissue cyst

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Toxoplasma

tachyzoites-

Giemsa stain 18

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Pneumocystosis

Pneumocystis jiroveci

Interstitial plasma cell pneumonia

Opportunistic parasite in AIDS

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Specimens

Lung biopsy

Impression smear

Tissue section

Sputum (induced sputum recommended)

5% KOH

Sputolysin (dithiothreitol)

Bronchial washing

Bronchoalveolar lavage (recommended)

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Staining

Toluidine blue O stain (recommended)

Cysts, 5 micrometer, appear lavender, with intense

staining marks

Some are “collapsed” cysts

must be distinguished from yeast

Giemsa stain for trophozoites and intracystic bodies

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Pneumocystis carinii- TBO

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Giemsa stain

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The End

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