Case #482 – December, 2018

A 48-year-old male immigrant from the Middle East underwent a stool examination for ova and parasites (O&P) as part of a refugee screening program. The lab technician observed dark brown-to amber-colored objects in wet mount preparations of formalin-ethyl acetate (FEA) concentrations of the stool sample. The objects measured 41-43 µm in length by 25-28 µm in width. Figures A-D show what was seen in the stool sample.

What is your diagnosis? Based on what criteria?

This case and images were kindly contributed by San Joaquin County Public Health Laboratory, Stockton, CA

Figure A

Figure B

Figure C

Figure D

This was a case of dicrocoeliasis caused by the trematode Dicrocoelium dendriticum. Diagnosis was based on the following morphologic features:

thick-shelled, dark brown embryonated eggs;
size range within that for D. dendriticum (35-45 µm long by 20-30 µm wide); and
presence of an inconspicuous operculum.

Most infections are light and asymptomatic. Eggs seen in stool can sometimes represent spurious passage after consumption of beef or sheep liver containing adult flukes. Additional specimens should be collected and examined to confirm a true infection.

More on Dicrocoelium dendriticum: https://www.cdc.gov/dpdx/dicrocoeliasis/index.html

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/.

Page last reviewed: March 6, 2019

Content source: Global Health, Division of Parasitic Diseases and Malaria