Happy Valentine's Day! Here is a special photo taken by Emily Fernholz, my awesome education specialist. These 2 little worms were found in a concentrated stool specimen and measure approximately 250 micrometers long. Identification?
Answer: Strongyloides stercoralis rhabditiform larvae
As noted by Florida Fan and Sugar Magnolia, these 2 larvae are "intertwined in romantic interlude" - "performing a romantic ballet". Perfect for Valentine's day!
The identification can easily be made by the size of these nematodes, their short buccal cavities (arrows in image below), and the genital primordium (less easily appreciated here).
The patient is a 65 year old Spanish woman who brought 3 worm-like structures to her physician. She had expelled the structures 30 minutes prior to presentation, and one was noted to still be moving. She reports no travel outside of Europe.
As mentioned by Luis, Florida Fan, Atiya, and Sugar Magnolia, these proglottids can be differentiated by other large tapeworms by the size and shape of the proglottids, and the presence of more than 12 uterine branches arising from the central uterine canal/stem:
Remember when counting uterine branches to only count them as they come off the central stem (primary branches), and only on ONE side (not both)!
As some readers mentioned, the proglottids of Taenia saginata are morphologically indistinguishable from those of T. asiatica; however, the patient's lack of travel outside of Europe makes infection with this latter parasite unlikely. Thanks again to Idzi Potters and the Institute of Tropical Medicine, Antwerp, for this interesting case!
The identification of this roundworm is based on its large size, tapered head and characteristic trilobate (3) "lips":
This worm can be further identified as a female based on its straight rather than coiled tail. Ali also astutely noted the presence of a "vulvar waist" - a narrowing at the junction on the anterior and middle thirds of the body, which also indicates that it is a female. Kamran was unable to express any eggs out of the worm; if found, the presence of eggs would also have confirmed the female gender. The size (30 cm) falls within the range of both male and female worms and therefore unfortunately cannot be used to identify the gender in this case.
Thanks to all of my readers for the excellent comments!
This week's case was generously donated by our long time contributor, Florida Fan. The following were noted in the stool of a apparently healthy man with no known travel history. The eosin wet mounts were photographed using the 40x objective, while the trichrome-stained slides were photographed using 100x. We don't make eosin saline mounts in my laboratory anymore; I had forgotten how pretty they can be.
Answer: Entamoeba coli trophozoites and cysts. Also present is a trophozoite of Dientamoeba fragilis.
This case from Florida Fan nicely shows the diagnostic features of E. coli, including the large size and >4 nuclei in the mature cyst stage:
Again, the colors of the trichrome and eosin saline mounts are beautiful.
As I mentioned above, there was also a D. fragilis trophozoite present. Because of its small size and indistinct chromatin features, this organism is significantly more difficult to identify. Here is the current case (bottom, left), as well as an idealized photo from my own collection (bottom, right). Note that the trophozoites have 1 to 2 nuclei with a 'fragmented' or 'fractured' chromatin pattern. The chromatin may also have a smudgy appearance.
Thanks again to Florida Fan for donating this case!
This week's case was generously donated by Dr. Piryanka Uprety and the excellent Clinical Microbiology and Hematology Laboratories at the University of Pennsylvania. The following structures were initially observed by a hematology fellow in a wet mount (40X) from a BAL specimen. Photographs and videos are courtesy of Joyce Richardson, Vivian Whitener, and Darrin Jengehino from the Hematology Laboratory.
Wet preparation of the BAL fluid with iodine showed the following:
Every week I will post a new Case, along with the answer to the previous case. Please feel free to write in with your answers, comments, and questions. Also check out my image archive website at http://parasitewonders.com. Enjoy!
The Fine Print: Please note that all opinions expressed here are mine and not my employer. Information provided here is for educational purposes only. It is not intended as and does not substitute for medical advice. I do not accept medical consults from patients.