Table 2.

Microscopy procedures for detection of Cryptosporidium spp, Cyclospora cayetanensis, and Cystoisospora belli

Procedure	Parasite	Advantages	Disadvantages
Wet mount (FEA concentrates)	Cryptosporidium spp	Concentration allows for better yield FEA concentrate can be used for DFA (see later in the table)	Oocysts may be confused for yeast and other nonparasitic elements Formalin waste
	Cyclospora cayetanensis	Concentration allows for better yield May be enhanced with differential interference contrast (DIC) or phase microscopy	Oocysts may be confused with nonparasitic elements Formalin waste
	Cystoisospora belli	Concentration allows for better yield May be enhanced with DIC or phase microscopy	Oocysts shed sporadically so multiple collections should be tested Formalin waste
Trichrome stain	Cryptosporidium spp	Not recommended	Oocysts do not stain well with trichrome; likely to be confused for yeast/fungal elements Specimens in PVA usually not concentrated
	Cyclospora cayetanensis	Not recommended	Oocysts do not stain well with trichrome Specimens in PVA usually not concentrated
	Cystoisospora belli	Not recommended	Not readily detected by trichrome Specimens in PVA usually not concentrated
Modified Kinyoun acid-fast (MAF) stain	Cryptosporidium spp	Uniform staining of oocysts; sporozoites often visible	Oocysts may be confused with yeast and other fungal elements that often stain red to purple with MAF
	Cyclospora cayetanensis	Oocysts can stain pink to red	Variability in staining; often many oocysts do not stain (ghost forms) and may be overlooked by inexperienced microscopists
	Cystoisospora belli	Sporoblasts stain red with MAF	Often there is shrinkage of oocyst wall, distorting form of oocysts
Hot safranin stain	Cryptosporidium spp	Uniform staining of oocysts	Requires heat; messy procedure
	Cyclospora cayetanensis	More uniform staining of oocysts	Requires heat; messy procedure
	Cystoisospora belli	Uniform staining of sporoblasts Oocyst wall less likely to collapse than with MAF	Requires heat; messy procedure
Ultraviolet microscopy	Cryptosporidium spp	Not available	Oocysts do not autofluoresce
	Cyclospora cayetanensis	Oocyst walls autofluoresce Allows for more rapid screening	Requires special filter with wavelength of 450–490 nm (not routine in most laboratories)
	Cystoisospora belli	Oocyst and sporoblast walls autofluoresce Allows for more rapid screening	Requires special filter with wavelength of 450–490 nm (not routine in most laboratories)
DFA	Cryptosporidium spp	Allows for rapid screening of Cryptosporidium spp Some allow for simultaneous screening of other organisms (eg, Giardia)	Requires microscopy with fluorescence capabilities Could be expensive if not used routinely
	Cyclospora cayetanensis	None available	None available
	Cystoisospora belli	None available	None available