Case #313 – December, 2011
A 29-year-old woman was seen by the medical unit at the U.S. Embassy in Indonesia for symptoms that included diarrhea for two weeks and vomiting for four days. A fecal specimen was collected for ova–and-parasite (O&P) testing. A diagnosis was made by the laboratorian at the medical unit and an aliquot was sent to CDC-DPDx for confirmation. Figures A and C show what was observed in moderate frequency using brightfield microscopy at 400x; Figures B and D show what was observed using ultraviolet microscopy of the same microscopic field. The objects of interest measured 8-9 micrometers on average. What is your diagnosis? Based on what criteria?
This was a case of cyclosporiasis caused by Cyclospora cayetanensis. Diagnostic features included:
- round, refractile oocysts within the size range for C. cayetanensis (Figures A and C).
- round oocysts with autofluorescent cell walls when viewed using UV microscopy (Figures B and D).
A permanent stained specimen record for cases of cyclosporiasis can be made by preparing a fecal smear (either formalin-fixed or unpreserved) and using a modified acid-fast or modified safranin staining procedure. Figures E and F show what was observed at 1000x magnification on a modified acid-fast stained fecal smear from this case.
More on: Cyclosporiasis
This case, and the specimen that the images were taken from, were kindly provided by The Medical Unit at the US Embassy, Jakarta, Indonesia.
Images presented in the DPDx case studies are from specimens submitted for diagnosis or archiving. On rare occasions, clinical histories given may be partly fictitious.
DPDx is an educational resource designed for health professionals and laboratory scientists. For an overview including prevention, control, and treatment visit www.cdc.gov/parasites/.