Case #489 – April, 2019
A teenage female college student from Texas observed a foreign object in her feces and took it to her school health clinic. She had no complaints of illness and did not present with any clinical symptoms. She also did not report any domestic or foreign travel history. The specimen was sent to the state public health laboratory for examination. Stool samples were ordered and tested by the school health clinic but the results were all negative for ova and parasites (O&P). The state lab then sent images of the foreign object as well as the physical specimen to the CDC for identification. Figures A and B show what the student observed in her stool. What test method would be useful in identifying the object? What is your diagnosis? Based on what criteria?
This case was kindly provided by the Texas Department of State Health Services
This was a case of taeniasis caused by the beef tapeworm Taenia saginata. Two other species (T. solium and T. asiatica) also cause taeniasis in humans, but use pigs as intermediate hosts. Separation of T. saginata and T. solium is usually accomplished by examination of mature proglottids using the India ink technique (Figure C), as the scolex is seldom recovered. Morphologic features presented included:
- Mature proglottids longer than broad (red vs green bracket, Figure B)
- Prominent unilateral genital pore, irregularly alternating sides (blue arrow, Figure B)
- The number of primary uterine branches counted (approximately 17) after injection of India ink into the genital pore (Figure C)
- Mature proglottids of T. solium have 7-13 uterine branches while those of T. saginata have 12-30 branches.
For more information on taeniasis, please click here: https://www.cdc.gov/dpdx/taeniasis/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/.