Monday, April 15, 2019

Case of the Week 540

This week's beautiful photographs are from Emily Fernholz at my lab. These objects were seen in a human stool specimen and measure approximately 80 micrometers in length. Identification?


The features are nicely appreciated on this video:

16 comments:

arba ager said...

Macracanthorhynchus

Bernardino Rocha said...

Agree with hatched egg (have a thick, dark brown and rugged surface, the eggs of Moniliformis sp. are smooth) and acanthor of Macracanthorhynchus sp. (M. hirudinaceus?).Did you use a sodium bicarbonate-sodium chloride solution to estimulate the hatching process?

Sir Galahad said...


Stadio cistacanto (cystacant) di Macracanthorhynchus hirudinaceous.

Sir Galahad said...

Oooopsss: hirudinaceus :-)

Marc Couturier said...

My favourite thorny headed friend!

Idzi P. said...

Human stool?

Anonymous said...

The rough outer shell indicates this is a Macracanthorhynchus. Now the question is what species?
M. hirudinaceus or ingens? This we need the head of the worm to identify. Here in Florida, we have millipedes and toddlers form the majority of incidental hosts after ingesting the thousand foot crawler.
Florida Fan

Old One said...

Not knowing the host or geographic location I'm not going to be very specific. Definitely an acanthocephalan egg. One can see the diagnostic characteristics of a multilayered membranes surrounding the egg. A darker and in this case a highly textured outer membrane. One end contains an acanthor which is basically a "crown of thorns" (no offense to the Notre Dame artifact the t was saved yesterday).

The egg size is a bit smaller than ranges reported for M. hirudinaceus but I must admit the egg images are a dead ringer for M.h.

These eggs are very resistant to environmental conditions and can remain infective for long periods of time.

These eggs preserve for long periods as well. I've had eggs preserved for over 50 years which remain visually as good as new.

Human coprolites have been found with identifiable acanthocephalan eggs.

Those crafty rotifers.


ParasiteGal said...

Sorry everyone - I should have specified. This is a human stool specimen. All of my cases are from human stool unless I specify otherwise (that's all we receive in my lab) :)

Blaine Mathison said...

Very interesting find in human stool, as Macracanthorhynchus rarely sheds eggs when in the human host.
One must consider this is spurious passage as well. Further collections should be performed to rule-out true infection; and the patient's stool should be grossly examined for adult worms.

Years ago when I studied under the late, great John Cross, he told a story regarding this from his years in Thailand(? can't remember location). Anyway, they were reading O&Ps one day and the stool specimens were loaded with Macracanthorhynchus eggs. They did some investigating and in the previous night (or night before that), the men in the village participated in a ceremony that involved eating raw pig intestines. The pigs must have been infected with Macracanthorhynchus and the people were just spuriously passing the eggs after ingestion of the infected intestines.

Idzi P. said...

Everything points to eggs of Macracanthorynchus sp.
Probably spurious as I have no knowledge of any case where cycle was completed in humans. Still, I would trade my soul to find this one in the lab!!! Never saw a case here in Belgium :’-(

Blaine A. Mathison said...

Macracanthorhynchus can reach sexual maturity in the human host (for the case published, the dissected worm was loaded with mature eggs); it's just for some reason the eggs are rarely seen in O&P exams. Either the female doesn't release them, or they are released in low numbers (or they are there, but because many technologists are unfamiliar with these organisms, they are just overlooked!).

Idzi P. said...

Thanks for this interesting additional comment Blaine!

ParasiteGal said...

Bernardino, we didn't actually purposefully try to hatch the eggs. That was just luck! The specimen came to us in our routine fixative (Ecofix).
Bobbi

Bernardino Rocha said...

Thanks for the information, it is a beautiful sequence of images.

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