(A and D) Modified Ziehl-Neelsen acid-fast staining of Cryptosporidium parvum/C. hominis oocysts (A) and a Cystoisospora belli oocyst (D). (A and D) Modified Ziehl-Neelsen acid-fast staining of Cryptosporidium parvum/C. hominis oocysts (A) and a Cystoisospora belli oocyst (D). (B and C) Unstained wet mounts for UV fluorescence microscopy showing autofluorescence of Cyclospora cayetanensis oocysts (B) and a Cystoisospora belli oocyst (C). (Parasite images courtesy of Marianne Lebbad; reprinted with permission.) Jaco J. Verweij, and C. Rune Stensvold Clin. Microbiol. Rev. 2014; doi:10.1128/CMR.00122-13