Case of the Week 777

 Dear Readers,

I am excited to announce that we are celebrating our 777th case! 

In honor of this milestone, we have a selection of 3 helminth eggs for you to identify. You win the parasite jackpot if you can get all three. There is an 'easy' and 'hard' version, so you get to take your pick.

EASY VERSION

Egg 1 (50 micrometers long)

Egg 2 (55 micrometers long)

Egg 3 (35 micrometers long)

HARD VERSION

Egg 1 (45 micrometers in diameter)

Egg 2 (95 micrometers long)

Egg 3 (One of 15 objects freed from a 4mm structure)

Answer to Case 776

 Answer to the Parasite Case of the Week 776: Toxoplasma gondii tachyzoites. As the name implies, the tachyzoite is the rapidly dividing stage of the parasite (tachy is from the Greek takhus meaning rapid, swift). Tachyzoites invade cells and divide rapidly within parasitophorous vacuoles, ultimately rupturing infected cells. Tachyzoites divide by endodyogeny, an interesting form of replication seen with some coccidia in which two daughter cells develop internally within the parent cell without nuclear conjugation. The parent cell is consumed in the process - yikes!

Shown here is the classic arc-shaped tachyzoite and 2 daughter cells resulting from the process of endodyogeny:

Case of the Week 776

This week's case is a brain biopsy from a middle-aged man with untreated HIV. The specimen appeared necrotic and bloody. Touch preps were made from the material and stained with Giemsa. From the images below taken with the 100x oil objective, what is your diagnosis?

Case of the Week 775

This week's case was inspired by Dr. Eric Rosenbaum. Several objects were submitted for parasite identification, including tan-white hair-like structures measuring 30 mm long by <0.2 mm wide. Here is their appearance by light microscopy. How would you sign this case out?

Answer to Case 775

Answer to the Parasite Case of the Week 775: Not a parasite. This is actually a hair from my house cat, Walter. Here he is keeping me company while I am trying to update a parasitology chapter:

As noted by Florida Fan, "The objects have neither external nor internal organs. We have a common saying: "No head, no tail, no guts, no parasites”

Most readers realized that this object was not a parasite, but a few did suggest that it was a tapeworm such as Rodentolepis (formerly Hymenolepis) nana, given the superficial resemblance of the cuticle scale and fragmented, 'ladder like' medulla to craspedote (overlapping) proglottids. However, we can differentiate the hair from R. nana proglottids by the smaller size, refractile nature, and lack of uterine structures. Check out the following comparison of our current case to an image of R. nana from a previous post donated by Dr. Emily Snaverly:

A few particularly savvy readers correctly guessed the nature of this object. There are a number of animal hairs that have this appearance, including some rodents (e.g., mice, chinchillas). You can see an amazing archive of mammalian hair images HERE. From the standpoint of the diagnostic laboratory, the important thing is to recognize that the submitted object is not a parasite and report it as such.

Case of the Week 774

This week's case features another great video from Dr. Rasool Jafari - an object identified from skin scrapings. What is this little arthropod?

Answer to Case 774

Answer to the Parasite Case of the Week 774: Demodex! The legs and gnathosoma (with mouthparts) are nicely demonstrated:

I can't quite tell if this is D. brevis, or Demodex folliculorum with a scrunched-up tail. 

We've had some great cases of Demodex on the blog over the years. Here is the list in no particular order:

Case of the Week 535 (with a poem from Blaine Mathison 😁), donated by Dr. Kabeer Shah.

Case 581 - showing an adult D. folliculorum and a video of 2 mites within a hair follicle. Also with a poem by Old One. This case was donated by Theodore Trejo and shows beautiful detail of the adult mite.

Case 702 - from the Mayo Clinic Mycology lab showing D. brevis on calcofluor white fluorescent stain.

Cases 278 - showing a pair of mites on calcofluor white fluorescent staining - with another poem from Blaine! I hadn't realized how many poems we have collected. This case was donated by Florida Fan.

Case 606 - donated by Dr. Sandeep T and showing a lovely long D. folliculorum.

Case 772 - This is the tricky case from last month with the twisted tail. Donated by Dr. Evis Nushi.

Case 503 - from Florida Fan with a really nice side-by-side view on light and fluorescence microscopy.

Case 334 - showing several D. folliculorum mites from eyelash scrapings. Donated by Dr. Robin Chamberland - with yet another poem by Blaine. All of the poems are different from one another, and very fun to read. 

Case 58 - the very first Demodex that I ever posted - 16 years ago!

Case 190 - a beautiful example of D. folliculorum in a hair follicle in an H&E-stained histopathology preparation. It was donated by Dr. Holkmann Olsen and is the best example I've ever seen of the mouthparts and legs in a histopathological section. 

Case 308 - and finally, an amazing case by Florida Fan that shows Sarcoptes scabei and Demodex folliculorum mites in the same image. 

I've been blessed to have so many fabulous case donations over the years. Many thanks to Dr. Rasool Jafari for donating this fascinating case.

Case of the Week 773

This week's case is generously donated by Dr. Rasool Jafari from the Department of Parasitology and Mycology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran. These objects were isolated from a patient and cultured in Modified TYI-S-33 medium. What parasite is this, and what are we seeing here?

Answer to Case 773

Answer to the Parasite Case of the Week 773: Giardia duodenalis trophozoites with 'falling leaf' motility. As nicely described by Idzi,this is a "Beautiful video material of Giardia trophozoites! Note that it’s official name now is “Giardia duodenalis”. We used to cultivate these critters on Keisters medium for educational purposes. Not easy though, so the more impressing this video by Dr. Rasool Jafari is! Kudos!"

Indeed, you can make out multiple characteristic features of Giardia trophozoites, including the 'tear drop' shape with 2 nuclei and a central axoneme when viewed anteriorly, a concave spoon-shaped appearance when viewed from laterally, anterior sucking disk, and even some trophozoites dividing by binary fission. I believe I've captured one here but defer to Dr. Jafari for confirmation. Many thanks again to Dr. Jafari for sharing this interesting case with us.

 

Case of the Week 772

This week's case is generously donated by Dr. Evis Nushi who identified the following structure in direct microscopy of skin scrapings. What is seen here?