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Monthy Case Studies - 2002

Case #81 - April, 2002

A stool specimen from a 20-year-old man was sent to the Oregon State Public Health Laboratory for examination. An FEA (formalin-ethyl acetate) concentration was performed and wet mounts prepared for examination. The objects seen in the images were present in moderate numbers and ranged in size from 33 to 40 micrometers (Figures A and B). The specimen also contained several larger objects that were forwarded to CDC for identification. The objects averaged 1 centimeter in length. The images show one of the submitted objects after clearing with lacto phenol solution, before (Figure C) and after injecting with ink (Figure D). What is your diagnosis? Based on what criteria?

Figure A

Figure A

Figure B

Figure B

Figure C

Figure C

Figure D

Figure D

Acknowledgement: This case was kindly provided by the Oregon State Public Health Laboratory.

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Answer to Case #81

This was a case of taeniasis caused by Taenia saginata. The eggs observed in this case were typical Taenia eggs; identification of Taenia to the species level cannot be achieved by examination of the morphologic features of the eggs alone. Examination of the proglottids is required to differentiate between T. saginata and T. solium. Specific identification of the Taenia sp. in the specimen was important because infection with T. solium can lead to cysticercosis (e.g., neurocysticercosis). The diagnostic features observed included:

  • the presence of Taenia eggs (approximately 30 µm) with the typical striated shell and hooklets (Figure B).
  • a proglottid with more than 14 primary uterine branches, which were visible in both the cleared and ink injected images. Taenia saginata proglottids typically have 15 to 20 uterine branches; T. solium proglottids have 7 to 13 branches.
Figure B

Figure B

More on: Taeniasis

More on: Cysticercosis

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Images presented in the monthly case studies are from specimens submitted for diagnosis or archiving. On rare occasions, clinical histories given may be partly fictitious.

 
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