Answer to Case 133

Answer: Taenia spp. ovum

I also asked "What is a serious complication of infection with this organism?"

Neuro Nurse answered this very well with the following:

"Cysticercosis results from ingesting T. solium eggs. Neurocysticercosis is the most common cause of seizure disorder in South and Central America.

Passing Taenia eggs in stool is indicative of tapeworm infection from eating meat with encysted larvae. Individuals passing T. solium eggs may infect themselves and others, causing outbreaks of cysticercosis.

Eggs of Echinococcus spp. are indistinguishable from those ofTaenia spp., but humans are intermediate hosts and do not pass Echinococcus eggs in stool."

I couldn't have said it better myself! Nice Job.

I will just comment that one cannot differentiate the eggs of T. solium (which may cause cysticercosis in humans) from the eggs of T. saginata (which does NOT cause human cysticercosis). Both eggs are small (approximately 30 microns in diameter), have a classic thick wall with radial striations, and may demonstrate internal hooklets (not well appreciated in this case).

The only way to definitively distinguish the T. solium from T. saginata is by examination of the gravid proglottids or scolex, since each have characteristic morphologic features. Epidemiologic features, such as history of eating undercooked pork or beef may also be helpful to determine which parasite is more likely to cause the infection.