Case #343 – March, 2013

Stool specimens were collected from residents of the Peruvian Amazon rain forest to evaluate the burden of helminth infections. Stool was collected and processed via Kato Katz at a laboratory in Cusco, Peru. The objects in Figures A–C were observed in high numbers (1,500 eggs/gram of stool) from a 54-year-old male patient. The objects measured on average 65 micrometers long by 33 micrometers wide. Clinical examination of the patient revealed that he did not have eosinophilia or elevated liver enzymes. What is your diagnosis? Based on what criteria?

Figure A

Figure B

Figure C

The objects shown in this case were the eggs of Capillaria hepatica. Diagnostic morphologic features included:

partially embryonated eggs within the size range for C. hepatica.
eggs possessing polar plugs and a striated shell.

The eggs of C. hepatica are not shed in the stool of the definitive host. Eggs are sequestered in the liver and are released into the environment following death and decomposition of the host, or consumption and excretion by a predator. The large number of eggs in this case suggests spurious passage following consumption of the liver of an infected animal. When eggs of C. hepatica are seen in stool, follow-up ova-and-parasites (O&P) exams should be performed to determine if the patient continues to shed them.