Tuesday, July 26, 2016

Case of the Week 406

This week's case was generously donated by Dr. Kamran Kadkhoda. This arthropod was found on a young girl near Winnipeg, in Manitoba, Canada.


Monday, July 18, 2016

Case of the Week 405

This week's case is from my own lab, with the beautiful images taken by Emily F. The patient is an asymptomatic male who underwent routine screening colonoscopy, which revealed the following:
Two objects were removed during colonoscopy and submitted to the Clinical Parasitology lab for identification:

 By manipulating the objects, we were able to express the following:


Sunday, July 17, 2016

Answer to Case 405

Answer: Trichuris trichiura (whipworm)

As pointed out by Arthur V and the other readers, the shape of the adult worms (narrow anterior end, broad posterior end) and the eggs are characteristic for this roundworm. Note that there is both a female (second image, straight posterior) and a male (image, curved posterior) in this specimen.

Another interesting feature of this case is that we were able to express both immature and mature eggs out of the female worm using blunt manipulation. The differences in maturity are responsible for the slightly different appearances of the eggs (kudos to the readers that pointed this out!) Here are the 2 eggs side-by-side for comparison:

Sunday, July 10, 2016

Case of the Week 404

This week's case was generously donated by Florida Fan. This structure was found in a concentrated stool specimen from a teenage male. It measures approximately 45 micrometers in diameter (shown at 400x total magnification). Identification?

Saturday, July 9, 2016

Answer to Case 404

Answer: Hymenolepis nana egg

As pointed out by Sheldon, BW, and Anon, this is a beautiful example of an H. nana egg, with refractile internal hooklets and 2 clearly visible polar thickenings. The arrows on the image below point out the polar thickening from which the polar filaments arise.

Thanks again for Florida Fan for donating this great case!

Sunday, July 3, 2016

Case of the Week 403

Happy Independence day to all of my American readers! Here is some red (magenta), white and blue for you - found in a modified acid fast-stained stool specimen:

 The objects measure approximately 35 micrometers in length. Identification?

Saturday, July 2, 2016

Answer to Case 403

Answer: Cystoisospora (formerly Isospora) belli

As pointed out by the readers, these are immature oocysts, since only 1 sporoblast is visible.

This is the state that this organism is shed in the stool of infected individuals. The oocysts then mature in the environment into their infective form, with the sporoblast dividing into 2 sporoblasts. The sporoblasts develop cell walls and become sporocysts containing 4 infective sporozoites each.

Thanks to Florida Fan for pointing out that the modified/hot safranin stain will also beautifully stain the oocysts of Cystoisospora (and other coccidia). The oocysts also exhibit striking autofluorescence using UV microscopy (excitation filter at 330-365 nm or 450-490 nm).

I hope you all had a safe and happy July 4th weekend!