Case of the Week 378

This week's case was donated from one of our superstar pathology residents, Dr. Heidi Lehrke. The specimen was a tan-white tissue, approximately 4 mm x 1 mm x 1 mm, that was obtained during colonoscopy and submitted for histopathologic processing. Stain shown is H&E. Identification?

40x total magnification

100x total magnification

400x total magnification

Answer to Case 378

Answer: Dipylidium caninum

As mentioned by Florida Fan, the key to identifying this case is to recognize the thin outer cuticle (consistent with a worm) and the clusters of eggs within thin-shelled packets.

 On higher magnification, the negative outline of hooklets can be seen within some of the eggs (if you use your imagination a bit).

And now - a poem from Blaine:

‘Waiter!’ the man shouted, ‘there’s a fly in my soup’

For which he was corrected, ‘No that’s a flea in the Siphonaptera group!’

‘What does it matter, it’s still a darn bug!!!’

To which replied our waiter who is entomologically smug:

‘But if you eat that lil’ critter there, you’ll have D. caninum in your poop!'

Case of the Week 377

Happy Holidays to all of my Creepy Dreadful Wonderful Parasite blog readers!

Here is a fun holiday-themed case: 'Santa' delivering 'gifts.' Who is Santa, and what is in the gifts?

Answer to Case 377

Answer:  Pthirus pubis, the crab louse; also nicknamed here 'Santa' louse.

As so nicely described by Kamran and Florida Fan, 'Santa' louse is coming down the hair shaft to leave a gift of a nit glued onto a hair shaft!

And a poem from Blaine:

Nice guys and gals will get toys in their stocking

But the naughty ones are sure to get something more shocking!

For the gift that keeps on giving is a parasitic louse

And that’s what you get for stepping out on your spouse!

So you’d better be good ‘cuz Santa Crab’s always watching!

Happy Holidays to all of my Readers! May the parasites you see not be your own.

Case of the Week 376

This week's case includes beautiful (and creepy) photographs and a movie from Dr. Graham Hickling at the University of Tennessee.

The following egg-laying arthropod was observed last month in her natural forest habitat. Identification?

Once you look at the photos, take a look at this video (set to music). It gives part of the answer away, but still leaves you with the task of determining the genus of this organism:
https://vimeo.com/148692758

Enjoy!

Answer to Case 376

Answer: Ixodes sp. adult female tick, laying eggs.

If you watched the video, then you probably noticed the "inverted U-shaped" anal groove (arrow below), which allows us to identify this tick as an Ixodes species.

So for those of you wondering what it looks like when all of these eggs hatch, I have some amazing follow-up photos for you from Dr. Hickling:

Case of the Week 375

This week's case is a bit of a challenge, and not something that has been featured on this blog before. It was generously donated by Dr. Kamran Kadkhoda.

The following objects were seen in the stool from a 30-year-old woman from Canada. No travel history is available. They measure approximately 50 micrometers in length. Identification?

Answer to Case 375

Answer: Not a human parasite; most consistent with a member of the Myxozoa, aquatic parasitic animals.

These are an incidental finding in human stool specimens, and usually indicate that the individual has recently consumed fish such as salmon. Arthur points out that microbiologists should be aware of this finding because of the very real possibility of mistaking these structures as human spermatozoa. This is especially important when dealing with cases of children and suspected sexual abuse. Here is the article that he recommended:

McClelland, R. S., D. M. Murphy, and D. K. Cone. "Report of Spores of Henneguya Salminicola (Myxozoa) in Human Stool Specimens: Possible Source of Confusion with Human Spermatozoa." Journal of Clinical Microbiology 35.11 (1997): 2815-818.

You can differentiate these structures from human spermatozoa by the consistent presence of 2 tail processes (rather than 1 tail in spermatozoa; only occasionally are 2 tails present), larger head structure with 2 polar capsules, and longer tail in relation to the head. Spermatozoa also have a longer defined neck region. Unfortunately, the appearances can be very similar, and therefore getting a dietary history may also be helpful.

And now a fun poem from Blaine!

Looking at this case after the last, you might ask ‘What is Bobbi doing?’

Pubic lice followed by spermatozoa, does she think this is amusing?

Alas this is only Myxozoa spuriously passed in the stool

After eating parasitized fish caught in a contaminated pool

And so Bobbi can now be absolved of a case that some might be misconstruing