Monday, June 1, 2020
Case of the Week 593
This week's case is from Idzi Potters and the Institute of Tropical Medicine Antwerp. Warning - it's a tough one! The patient is a young woman with recent travel to the Democratic Republic of the Congo. While there, she worked with primates, and developed a short episode of fever, rash and diarrhea. Upon return to Belgium, a check-up was done, including a stool parasite exam. Apart from Giardia duodenalis and Trichuris trichiura, the following structures were found (measuring about 50 to 55 µm in length). What is your differential diagnosis?
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14 comments:
Larvated nematode eggs, thin shelled, and size consistent with eggs of Strongyloides. Eggs were recovered from fresh feces. Because the patient was working with nonhuman primates in subSaharan Africa it is possible that she became infected with Strongyloides fuelleborni subspecies fuelleborni, which commonly cross infects with humans, is passed as a larvated egg, may cause a rash at site of skin penetration and may cause diarrhea. As for the fever, I don't know, perhaps some other pathogen.
I should mention that the closely related primate nematode S. fuelleborni subspecies kellyi also infects humans but so far is not found outside the East Indies and infects only children.
Thin shell, embryonated egg of nematode; either hookworm or Strongyloides. Stool culture is recomended
This is a tough one, and I was never great at zoonotic or otherwise non-human strongyle nematodes. The proposed idea of Strongyloides fuellborni is a great idea. However, I cannot rule-out the spurious passage of a plant or soil nematode.
Interesting thought Blaine. I once had a case of a canine shedding similar larvated eggs. They turned out to be eggs of a root knott nematode (Meloidogyne sp.). The new hatched larva would contain a pharyngeal stylet which could be visible within the egg. Egg measurements of Meloidogyne tend to be a bit larger than Strongyloides. It might be worthwhile to find out if the patient has been eating knotty rootlet covered carrots
Idzi just gave us a very tough piece of cake. Monkey business has never been my cup of tea. I will follow the discussion of the authorities on the subject to learn some more.
Florida Fan
could all not fit into the picture of Ankylostoma ceylanicum infection or related animal hookworm infection?
pvt, netherlands
Hi pvt,
You raise a good point, but...
To my knowledge, the animal hookworm species wouldn’t reach maturity in humans.
Kind regards,
Idzi
After more surfing the web, I would go with non human primate Strongyloides app. That's only my wild guess when it comes to monkey business.
Florida Fan
I am only posting in admiration of my colleague's responses and the comment, monkey business by Florida Fan. Without the zoonosis teaser, would have said a decorticated mature Ascaris egg, though perhaps small for that. Cheers Bobbi and Antwerp!
i am sure this resource is old hat to most and it is incomplete (with reason, i'm sure) however... it is a starting point for a case like this:
https://www.cdc.gov/dpdx/diagnosticprocedures/stool/morphcomp.html
(and if there are better ones, PLEASE share! I very much appreciate your collective mentorship!)
eagerly awaiting the detailed conclusion and wondering if the stated coinfections will play a part in the differential (along with the H&P provided)
Actually Old One's identification makes sense. In humans infected with Strongyloides stercoralis, we do not find the eggs in the stool of the patient, mostly rhabditiform larvae or in older unpreserved sample there may be filariform larvae. However the non human primate parasite does shed the eggs in the stool.
Once again my thanks and respect go to Dr. Pritt and everyone on the Blog.
Florida Fan
I just want to comment to a couple things above. Yes, Ancylostoma ceylanicum does reach adulthood and causes intestinal infection in humans. It is actually considered one of the leading causes of intestinal hookworm infection in SE Asia and has also been documented in Australia.
This case is not A. ceylanicum (I don't think it is hookworm either way), but I just wanted to clarify the above comments about A. ceylanicum.
Hi Blaine,
That’s completely correct!
A. ceylanicum has indeed been identified as an important species infecting also humans in Asia, and reaching maturity in humans too.
Thanks to clarify this!
Cheers!
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