Cyclospora (acid-fast stain)

Photomicrograph of a fresh stool sample prepared using a 10% formalin solution and stained with modified acid-fast stain; four Cyclospora cayetanensis oocysts may be seen. It is important to distinguish Cyclospora oocysts (diameter 8 to 10 microns) from those of Cryptosporidium, which are also acid fast but smaller (diameter 5 microns).

Compared with wet mount preparations, the oocysts are less perfectly round and have a wrinkled appearance due to this method of fixation, and the staining is variable among the four oocysts.