Case of the Week 622

 This week's case was graciously donated by Dr. Kyle Rodino, one of our outstanding former Medical Microbiology fellows. The following specimen was submitted to the clinical microbiology laboratory in vodka (which deserves extra points for creativity). Identification?

Answer to Case 622

 Answer to the Parasite Case of the Week 622: drunken Pediculus humanus capitis

There are pretty entertaining and interesting comments that I would encourage you to read if you are interested! Here are some of the key findings in this case:

Thanks again to Dr. Rodino for donating this interesting case.

Case of the Week 621

Happy New Year everyone! We are going to kick off the New Year with a fascinating (and challenging) case by Idzi Potters and the Institute of Tropical Medicine, Antwerp. 

From Idzi: While I was rummaging through the education-samples, I stumbled upon a strange-looking, small vial, containing a liquid from unknown origin. When I looked at the identification label, I was quite surprised to find a name that sounded like a very exotic parasite…

During a quick microscopical examination, I found eggs of about 60-70 µm in length.

Who can guess which parasite I found? Hint: the source ended up being a cyst near the ear from an African man.

Answer to Case 621

 Answer to the Parasite Case of the Week 621: Poikïlorchis (Achillurbainia) congolensis.

Wow, I am so impressed with how many of you got this identification. This rare parasite was first described in Nature in 1957 in a man from the Belgian Congo. 

From Idzi: Poikilorchis congolensis, or alternatively Achillurbainia congolensis -as the genus Poïkilorchis (Fain and Vandepitte, 1957) was regarded by Dollfus as a synonym of Achillurbainia (Dollfus, R. P., 1966. Personal communication).

As far as I have found in the literature, it has been described in humans only eight times up ‘till now, although some authors suggest that some of the reported cases of Paragonimus (especially in Africa) could be in fact cases of Poïkilorchis infection.

Although its hosts are not known for sure, Poïkilorchis congolensis is considered to be a zoonosis, with the common final host probably being leopards (and maybe also giant rats?) and intermediate hosts being probably freshwater crabs.

The infection typically produces subcutaneous retroauricular cysts, which contain as well the eggs as the adults. Nevertheless, in many (human) cases only eggs are found in the cyst.

In the literature, I found human cases in Central and West Africa, Sarawak (Malaysia), possible also one in China…

Idzi and the vial of of Poïkilorchis congolensis eggs.

As many of you noted, these eggs look like those of Diphyllobothrium/Dibothriocephalus spp., but the source is inconsistent with this identification. Similarly, the eggs resemble those of Paragonimus spp., but the size is too small. Other helminths that may be found in this location include cestode larvae (Taenia solium, Echinococcus granulosus complex), Lagochilascaris minor, and Gnathostoma spp., but none would have the appearance seen in this case.

So this is over all a fantastic case, and a great way to start off the new year! Thanks again to Idzi for donating this case.

Case of the Week 620

This week's case is a nice straight-forward one because - spoiler alert - we are going to have a really fun challenge from Idzi Potters next week to start off our new year. 

The following worm was found during routine colonoscopy. Identification? For 'extra credit' - which end is anterior? And is this a male or female?

Answer to Case 620

 Answer to Parasite Case of the Week 620: Trichuris trichiura, a.k.a. "whipworm". This is a male, as evidenced by its curled tail and copulatory spicule (note the location of the anterior and posterior ends):

Be sure to check out the comments section to see all of the creative comments that go with this case!

Case of the Week 619

 Dear readers,

Wishing you and your family a very happy, safe and healthy holidays. To celebrate the season, I thought I would share a few of my favorite photographs from my 2020 calendar - all decked out for the holidays. Can you tell what they are?

Answer to Case 619

Answers to Parasite Case of the Week 619: Trichuris trichiura, Schistosoma couple, and Hymenolepis nana.

Case of the Week 618

 This week's case features some photos from a cool histopathology case I found in my archives. The source is "large single liver cyst". Identification? What cool things do you see in these images?

Answer to Case 618

 Answer to Parasite Case of the Week 618: Echinococcus granulosus sensu lato species complex

There are many cool features in this cool case. Here are just a few that I thought were worth pointing out:

First, note how you can see a portion of all of the layers of the cyst. Going from the outside-inward, you can see the compressed host tissue, outer most parasite-derived layer (laminated layer), the granular layer, and several brood capsules, each containing multiple protoscoleces.

Within the individual brood capsules are many inverted protoscoleces arising from the granular layer. We even managed to get a section showing how one protoscolex is attached to the cyst granular layer by a thin stalk. Numerous, variably-sized, calcareous corpuscles are also seen: 

Another cool feature in this case is the presence of degenerating protoscoleces within some of the daughter cysts, resulting in freed hooklets. The resultant gritty fluid is referred to as hydatid sand. 

Protoscoleces don't usually evert unless they have been ingested by the definitive canid host. They then mature into the adult worm and live in the gut of the host. I'm guessing that eversion occurred in this case as part of the degenerative process.

Thank you for all of the comments!