Answer to Case 320

Answer:  Dipylidium caninum proglottids containing numerous egg packets.  Each of the small structures shown in the low power images is a (very) gravid proglottid:

On higher magnification, the characteristic eggs packets are seen, each containing eggs with hooklets (you have to use your imagination a bit to see the hooklets).

Although the eggs look a little different than what we see in stool preparations, I think that, with a bit of practice, parasitologists can learn to correlate these 2-D section to our familiar 3-D objects , given that D. caninum is the only parasite in humans to produce these characteristic egg packets.  Thank you all for writing in!

And now a poem from Blaine Mathison:

A baby cuddling with a kitten is such a cute scene

Until the kid accidentally swallows an infected cat flea

For down in his intestines a new pet does come

For he’s host to the cestode Dipylidium caninum 

shedding motile proglottids in the kid’s soiled Onesie