Table 2.

Outline of stains used in histopathological evaluation

S.No	Stain	Morphological features	Remarks
1	Hematoxylin and Eosin	pale pink, ill-defined morphology	Most common tissue stain, should raise the suspicion of microsporidia. Appearance may resemble yeasts, needs confirmation by other stains
2	PAS	pink to purple in colour, ill defined morphology	Poorly stained, but the pink dot at the pole could suggest microsporidia. Not confirmatory
3	Giemsa	stain not taken up be cell wall, appears blue,	Stains the organism blue, but does not stand out against the blue background with also shows granular debris Easy to perform
4	GMS	oval to round, brown in colour, internal band is easily spotted, background green	Good stain, highlights the organism again the background under low magnification. Expensive reagents, time consuming
5	CFW	blue, oval, diffusely fluorescing spores, sometimes only spore wall fluoresced	Easy for experienced observer, but can be confused for yeasts. Produces high background noise Cannot be done without a fluorescence microscope
6	Acridine orange	oval, refractile, yellowish-green to orange fluorescence, no demarcation from the background	Easy for experienced observer, but can be confused for yeasts. Produces high background noise Cannot be done without a fluorescence microscope
7	Gram	gram variable, waist band visible, poor contrast from background, plenty of inflammatory debris	Economical, easy to perform. Variable staining, high background noise is a limitation. Microbiologists find it familiar and easy to extrapolate with cytologic findings
8	Masson's Trichrome	spores appeared red against a blue background, ill-defined internal morphology	High background noise, difficult to standardize the stain. Pathologists familiarity more than microbiologists
9	1% acid fast	oval, bright red with a darkly stained belt across the spore, visible against a blue background	Good contrast, easy interpretation, less time and economical. Unstained forms can also be found
10	Gram's chromotrope	spores appear purple to pink against green background, characteristic belt visible	Provides good contrast, easy to detect the organism under lower magnification. Has the added advantage of Grams and Massons trichrome, less time