Sunday, April 23, 2017

Case of the Week 443

This week's case was donated by Dr. Tom Grys. The patient is an immunocompromised man with hemophagocytic lymphohistiocytosis (HLH) and fever. He reports travel throughout the United States and Italy. Bone marrow biopsy revealed the following:


Sunday, April 16, 2017

Case of the Week 442

This week's case was generously donated by Dr. Bryan Schmitt and Kayla Kirby. The patient is a middle-aged man from West Africa who presented with a chief complaint of worms in his stool. Four tan-white objects were received in saline and an egg was expressed from one of them.


Saturday, April 15, 2017

Answer: Case 442

Answer: Taenia saginata proglottid and egg

This was a remarkable case in that the fresh proglottids clearly showed the characteristic uterine branching pattern without the need for clearing, mounting, or India ink injection. Instead, you can see all of the lateral branches coming off of the central uterine stem with surprising clarity:
By counting the uterine branches, you can differentiate Taenia solium from T. saginata/T. asiatica. 
Note that you should only count the primary branch points coming off of the central uterine stem. Also, it is important to count only on one side. As you can see from my line drawing above, there are ~15 branches that can be identified in this specimen, thus making this either Taenia saginata or T. asiatica. Given that this patient was from Africa, we can narrow the differential to T. saginata, the "beef" tapeworm. Upon questioning, the patient admitted to frequently eating undercooked beef, which is the route of human infection.

As a confirmatory measure, the proglottids were manipulated to release eggs like the one shown below, which confirm without a doubt that this is a Taenia proglottid. Note the characteristic morphologic features including internal hooklets (one is clearly seen) and thick outer wall with radial striations.
Here is a fun accompanying poem from Blaine Mathison:

If one eats undercooked meat in Africa it’s a general rule
It’s likely he will end up with proglottids in his stool!
As deeper into your ID you delve,
Count those branches more than twelve!
You’ll see it’s T. saginata, just like you learned in school!

Thank you again to Bryan and Kayla for donating this great case.

Monday, April 10, 2017

Case of the Week 441

This week's case was generously donated by Dr. Nipunie Rajapakse. The following object was passed in the stool of a teenage boy with recurrent fevers and constipation. His only travel outside of North America was Portugal and Hawaii. Treatment with an antihelminth was ineffective at alleviating his symptoms and follow-up stool exams were negative.


Sunday, April 9, 2017

Answer to Case 441

Not a parasite; most closely resembles a slice of onion/onion skin. If you do an internet search for sauteed onions, you will find many beautiful (and tasty looking) examples of similar-appearing structures.

This case is a great reminder that many food partially-digested objects can be seen in human stool specimens, and many of them (e.g. bean sprouts, bubble gum, citrus pieces, onion slices, tomato skins) can be seen an mistaken as parasites. The definitive way to differentiate these objects from true parasites is to look them under a dissecting microscopy and by light microscopy if necessary, examining the consistency and looking for eggs (as suggested by Michigan Micro).

Monday, April 3, 2017

Case of the Week 440

This week's case was from a young boy who had been unsuccessfully treated for pinworm infection. An apparent worm was submitted to the laboratory on a pinworm paddle (Swube®):

Given the unusual morphology, the specimen was cleared with Citrisolve and mounted on a slide for examination:

Identification? Many thanks to Florida Fan for donating this week's case!

Sunday, April 2, 2017

Answer to Case 440

Answer: Dipylidium caninum proglottid containing characteristic egg packets.

This is such a great case because it shows the characteristic morphology of this cestode, as well as how a clinical misdiagnosis (in this case, as pinworm) led to incorrect therapy, which was remedied following correct identification in the clinical microbiology laboratory. Thanks again to Florida Fan for donating this case. Here are some of the key features of this case:

Saturday, March 25, 2017

Celebrating 10 years of Creepy Dreadful Wonderful Parasites

Thank you for joining me today to celebrate 10 years of blogging with Creepy Dreadful Wonderful Parasites! I can't believe that my very first entry on this blog was posted on March 25, 2007.

For my celebration, I invited all readers to submit their artistic parasite creations, and was amazed by all of the outstanding entries I received. They are all below for your viewing pleasure. I entered the name of each person who submitted something into a hat and then randomly selected 5 names.
And the winners are:
  • Rachael Liesman
  • Sidnei Silva
  • Prakhar Vijay
  • Melanie Bois
  • Kevin Barker
I will contact each winner separately about your prize (choice of a parasite calendar, phone case, or mug).

Fabulous parasite creative works (by category):


Giardia and Leishmania, adorned in traditional Brazilian costumes. 
Illustrated by Sidnei da Silva

Trypanosoma brucei
Charcoal sketch by Emily Evans

Schistosoma couple
Painted on canvas by Prakhar Vijayvargiya

Tsetse fly and Reduviid bug
Illustrated by Amy Gallimore

Plasmodium berghei with a "Friday feeling Smile" by Kevin Barker

Looking for anisakids - a fish dissecting party with Rachel Vaubel, Melissa Blessing, Xuemei Wu, Emily Patterson, Melanie Bois and Heidi Lehrke

Cerebral toxoplasmosis by Melissa Blessing


Dipylidium caninum scarf by Heidi Lehrke

Giardia kiteii by Florida Fan

Leishmania cross-stitch by Tiffany Borbon

Dracunculus medinensis and myiasis cupcakes by Rachael Liesman

Plasmodium falciparum cookies by Emily Fernholz

Dermatobia hominis baby by Reeti Khare

Dipylidium caninum by Heather Rose

"Tubes of blood" for FIL (filariasis) and MAL (malaria) testing by Felicity Norris, Aimee Boeger and Brenda Nelson (note that Aimee is a green top tub (heparin) which we don't accept in my lab, so she has been 'cancelled'

Taenia solium with detachable 'proglottids' by Jadee Neff and family

Taenia solium and eosinophils with Rose Sandell and Melanie Bois

"Entamoeba histolytica/E. dispar/E. moshkovskii/E. bangladeshi and E. hartmanni - who can tell them apart?" with Patty Wright, Corrisa Miliander, Heather Rose, Emily Fernholz and Kelli Black

An engorged and gravid tick by Elli Theel

Giemsa by Jane Hata

A fish with a tapeworm by Rachael Liesman

by Blaine Mathison
Twas the night before Christmas when all through the house
the fleas were all nestled in the fur of the mouse.
They paired with their loved ones under a sprig of mistletoe,
A gift from Cousin Chigoe, from down south in the toe.

The larvae were pupating in the bed of the host,
carrying Dipylidium cysticercoids, an infectious dose!
The Yersinia pestis churned in the foregut
until such time when the proventriculus would erupt!

All of a sudden there appeared such a clatter!
The fleas sprang from the fur to see what was the matter.
Crawling up the leg of the host, with such stealth and so quick,
was the holiday icon known as St. Tick.

“Now Ixodes, now Dermacentor, and Amblyomma!
On RhipicephalusOrnithodoros, don’t forget Hyalomma.”
He got right to work and delivered the fleas' presents
full of pathogens to spread to medieval peasants,

Then he sprang to his sleigh and let out a whistle,
Then they took off into the night like a guided missile.
But I heard him exclaim as flew out of sight,
Merry Christmas to all, and to all a good bite!

Monday, March 20, 2017

Case of the Week 439

This week's case is anticipation of Saturday, March 25th, in which I will be celebrating the 10-year anniversary of Creepy Dreadful Wonderful Parasites. As part of the celebration, I am asking all readers to consider sharing a photograph of your parasite creations - be it a painting, photograph, parasite-related costume, poem or other creative work. I will enter the name of each person who submits something in a drawing and will select 3 winners for creepy dreadful wonderful parasite prizes.

I have already received multiple entries, and have chosen to highlight this excellent entry from Florida Fan - a parasite kite! Can you guess the parasite?

Sunday, March 19, 2017

Answer to Case 439

Answer: Giardia!

This lovely kite by Florida Fan was also identified as: Giardia kitelia, Giardia flier, and Giardia lampshadia

Be sure to check out all of the fantastic parasite creations that were submitted for my 10-year celebration.

Tuesday, March 14, 2017

Celebrating 10 Years of Creepy Dreadful Wonderful Parasites - Submit your parasite works of art to be entered in a drawing!

Dear Readers,
Thank you for all of the great suggestions on how to celebrate my 10 years of blogging. After some consideration, I've decided to use this as an opportunity to appreciate the creativity of all of my readers.

As we know, parasites can be creepy and dreadful, but they can also be wonderful and beautiful in their own right. Many of you have produced delightful parasite-related creations  - original photographs, paintings, sculptures, poems, short stories, and even kites! Therefore, please consider sharing your creations with the other readers by sending me an electronic copy of your work that I can post on my blog. I will enter the name of each person who sends me something into a drawing and select 3 individuals to receive Creepy Dreadful Wonderful Parasite prizes. I will also display all of the photos/creative works that are submitted on my blog post on March 25th, 2017 - the exact date of my 10-year anniversary.

Submissions are accepted immediately! You can submit as many as you want, but your name will only be entered once. I can't wait to see all of your works of art!

Monday, March 13, 2017

Case of the Week 438

I apologize that this week's case is rather disturbing - and not in usual the creepy crawly parasite way.

The following structure was coughed up by a 70-year-old woman with advanced stage lymphoma. She had recently received chemotherapy consisting of rituximab, ifosfamide, carboplatin and etoposide (R-ICE). At the time, she was quite ill and in the intensive care unit. Likely identification?

Sunday, March 12, 2017

Looking for Ideas - Celebrating 10 years of Creepy Dreadful Wonderful Parasites

I can't believe that my first post was almost 10 years ago now - on March 25th, 2007. I feel like I have to do something special for my 10-year anniversary on 3/25/2017.

So I'm looking for ideas. Maybe a contest with prizes? I have lots of Creepy Dreadful Wonderful Parasites 'swag' to give away, including calendars, magnets, greeting cards and iPhone cases :)

Please email me with ideas.

Answer to Case 438

Answer: Sloughed esophageal mucosa.

Although this has a superficial appearance of a worm, it actually consisted of a floppy tubular structure (not fully shown in the images) composed of the outer layer of this patient's esophagus. This is a well-described phenomenon that is most commonly seen in older patients who are receiving a number of medications. It has also been seen with infectious and bullous diseases. Here are a few references which describe this phenomenon:
Carmack et al. 2009
Purdy et al. 2012
Moawad et al. 2016
Fortunately, this is usually a self-limited condition and patients fully recover.

The following images are from a similar case that was donated by Dr. Julie Ribes.

Microscopy revealed show that the structures are composed of sheets of squamous epithelial cells.

Some readers also suggested that the original case represented mucous casts, which is another good consideration. However, mucous casts would appear more solid rather than tubular.

The most important consideration in this case is not to mistake the structures for worms, since that would lead the clinical team down the wrong path in their evaluation.

Many thanks to Dr. Ribes who provided the amazing images of her similar case, and to Dr. Grys for providing the original case.

Tuesday, March 7, 2017

Case of the Week 437

This week's case was generously donated by Dr. Mike Mitchell and Janice Gotham. This is a trichrome-stained stool specimen. While the diagnosis may seem straight-forward, there is a question in what to call this organism based on some new proposed nomenclature changes. Please tell me how you think this parasite should be reported out to the patient's physician. Dr. Stensvold, I'm particularly interested in your opinion!

Monday, March 6, 2017

Answer to Case 437

Answer: Blastocystis species

I had posed the question about nomenclature to see how labs are currently reporting this parasite when it is identified in stool specimens by microscopic examination.

Originally, only B. hominis was thought to infect humans, while other species infected other animals. However, we now know that humans can be infected with the same organisms as many other hosts, and differentiation between these species is not possible by morphologic examination alone. Therefore, the most accurate way to report this organism when observed in human stool specimens is "Blastocystis sp." rather than "Blastocystis hominis".

This may cause some confusion among clinicians and therefore, providing some education about the change is recommended.

Some other fun taxonomic facts about Blastocystis spp.:
  • It was first described by Alexeev in 1911
  • It was thought to be a yeast due to its morphologic appearance
  • Later, Blastocystis was re-classified as a sporozoan protozoal parasite 
  • Blastocystis spp. is now believed to be a stramenopile - a group that includes diatoms, brown algae and mildew. The only other stramenopile to infect humans is Pythium. (HERE is a nice article in the Journal of Clinical Microbiology about human infection with P. insidiosum)
For more information about Blastocystis spp., check out the excellent BLOG by Dr. Christen Rune Stenvold. Many thanks to Dr. Graham Clark for his assistance with describing Blastocystis taxonomy is a comprehensible fashion.

Tuesday, February 28, 2017

Case of the Week 436

This week's case was generously donated by Dr. Sabarinathan from Madras Medical College in Chennai, India. The patient is a young man with a 2-week history of epigastric pain and vomiting. Physical examination was normal, and a complete blood count showed only a mild anemia (hemoglobin of 9.8 g/dL). An ultrasound of the abdomen was normal and so an upper gastrointestinal endoscopy was performed. This is what was seen:

Monday, February 27, 2017

Answer to Case 436

Answer: Ascaris lumbricoides

Although we don't have the worms to examine in this case, the presence of multiple large tan-white worms with a smooth outer cuticle within the lumen of the intestine is strongly consistent with A. lumbricoides. The female A. lumbricoides can get quite large, reaching lengths of 35 cm!

One reader also raised the possibility of anisakiasis given that these worms were found on an upper endoscopy. However, the large size would exclude anisakid larvae given that they only reach a few centimeters in length. Also, the presence of multiple worms would be unlikely for anisakiasis, since usually only 1 larva is seen in these cases. Finally, anisakids try to recapitulate their lifecycle in their marine mammal host and embed into the gastric or intestinal mucosa. This type of behavior was not seen in this case.

Sunday, February 19, 2017

Case of the Week 435

This week's challenging case was donated by Dr. Emily Hall. The patient is a previously-healthy toddler who began acting unusually fussy and refused to ambulate. Examination reviewed a thin black object under the skin of her right foot. Extraction was unsuccessful and the child was playing and ambulating at the end of the visit and was therefore sent home. The child was brought back the following day because the object had moved approximately 3 cm within a 24 hour period in the semilunar pattern shown in the image below:
At this point, the object was removed and sent to the parasitology lab. Rather than showing you the images of the object that was extracted, I thought I would ask for your diagnosis based on the clinical image alone. I will show you the images and provide the diagnosis next week!

The image is shown with permission from the mother.

Saturday, February 18, 2017

Answer to Case 435

Wow, this case generated a lot of interest, with requests for the answer when I didn't post yesterday. My apologies for leaving you all hanging!

This is a case of a non-parasitic fiber that had been transcutaneously implanted and migrated under the skin due to physical pressure (i.e. walking). Although the presentation was suggestive of a cutaneous parasitic infection such as cutaneous larva migrans (CLM), the length of the object and dark color were not consistent with any human or zoonotic parasite. Several readers pointed out specifically that the larvae that cause CLM are microscopic and therefore would not be visible to the naked eye. Also, the path formed by a migrating worm would be more serpiginous rather than the semi-lunar pattern observed here. Other subcutaneous or intra-epidermal/dermal worms such as Loa loa, zoonotic microfilariae, and Dracunculus medinensis were also suggested but rightly discarded by readers because of the size and color of this object. There is no parasite, to my knowledge, that would have this appearance and be present in this location in human skin.

One intriguing suggestion was that this was cutaneous pili migrans (CPM) - an excellent thought. CPM is a phenomenon in which a hair grows within the skin rather than up and out of the skin, and is seen as long dark object just below the skin's surface. This is most common on hair-bearing regions of the body and would be unusual on the sole of the foot. However, removal of the object would be required to rule out  CPM. Therefore, this is exactly what we did. Here are photographs of the object that we removed (cut in half):

As you can see, it looks to be a synthetic fiber and not any type of worm. It was extremely resilient, and while bendable, did not easily break. Just for fun (and because I knew you would all want to know), we analyzed the fiber using infrared spectrum analysis, which showed it to be most consistent with azlon, a synthetic fiber commonly used to make clothing and household objects.

Thanks again to Emily Hall for donating this fascinating case!