Answer to Case 750

 Answer to the Parasite Case of the Week 750: Bertiella sp. proglottids and egg.

Kudos to everyone who got this right! As noted by Idzi, "At first I thought this would be plant material, but the egg is quite typical for Bertiella sp. showing the typical pyriform apparatus inside. Secondly, in the third histology picture I think I see calcareous corpuscles, typical for and consistent with a cestode structure, together with an eosinophilic acellular tegument. So I'll follow Florida Fan with the diagnosis of Bertiella sp. infection.

Here is the characteristic egg with the pyriform apparatus inside:

Our previous case (565) shows this in greater detail, along with the short and wide proglottids (with a disturbing resemblance to bow tie pasta). 

When looking at the proglottids from cases 565, one can see how sectioning may reveal the 'interesting' histopathologic appearance that we see in this case.

Previous case:

Current case:

Sarah Sapp notes on X/Twitter that the preparation is...rather creative. Ideally, proglottids are sectioned so that we see them in coronal section. This appears to be a sagittal section. However, it can be very challenging to orient such a small object for histopathology sectioning, especially when the the type of material is not known. Fortunately, the acellular tegument and calcareous corpuscles allow for identification of this object as a cestode.

Thanks again to Drs. Sullivan and Nash for donating this interesting case!

Answer to Case 565

Answer to Parasite Case of the Week 565: Bertiella species

This case nicely demonstrates a short chain of proglottids and egg (expressed from the proglottids) of Bertiella - a tapeworm of non-human primates that only rarely infects humans. You can read more about this fascinating parasite at the CDC DPDx website.

The proglottids are very short and wide, thus giving this small segment of proglottids the appearance of 'bow tie' pasta as several of my readers pointed out! (arrows point to some of the individual proglottids)

Bertiella eggs have an internal pyriform apparatus which is difficult to make out in this case. It is better seen in my previous case from 2012: Case of the Week 193.

Thanks again to Professor Agnes Kurniawan from the University of Indonesia who donated this case.

Answer to Case 193

Answer: Bertiella sp. eggs

Great job everyone! I thought this would be a tough one, but received lots of correct answers. Bertiella is a genus of cestodes (tapeworms) that typically infect non-human primates, although humans are also occasionally infected.

The diagnosis can be made from the presence of the classic pyriform apparatus, an inner membrane with projections around a 6-hooked embryo.

Answer to Case 777

 The Answer to the Parasite Case of the Week 777 is up - and it's a jackpot of parasite eggs! 

Easy version:

• Trichuris trichura
• Ascaris lumbridoides
• Taenia sp.

Hard version:

• Bertiella sp.
• Acanthocephalan egg (M. moniliformis - expressed from the worm so slightly immature, which is why it's not as clear as you would expect)
• Inermicapsifer or Raillietina (Actually Inermicapsifer, but as Idzi mentioned, you cannot tell the egg capsules apart from these two). 

How many of you got the jackpot?!?

Thank you for playing for more than 18 years and 777 cases 😉