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[Cyclospora cayetanensis]

Cyclospora cayetanensis oocysts are spherical, 7.5-10 µm in diameter and unsporulated when passed in feces.  Sporulation in the environment is temperature-dependent and may take one to several weeks for an infective oocyst to contain two sporocysts, each containing two sporozoites.  Oocysts of C. cayetanensis will autofluoresce under ultraviolet (UV) microscopy.

A, B:  Oocysts of C. cayetanensis viewed under differential interference contrast (DIC) microscopy.  The refractile globules are easily visible under DIC.

C, D:  Oocysts of C. cayetanensis viewed under DIC microscopy.  Two sporocysts are visible in Figure C.

E:  A pair of oocysts of C. cayetanensis viewed under DIC microscopy.
F:  Rupturing oocyst of C. cayetanensis viewed under DIC microscopy.  One sporocyst has has been released from the mature oocyst; the second sporocyst is still contained within the oocyst wall.