Monday, November 18, 2019

Case of the Week 569

This week's case was captured by my awesome Parasitology Education Specialist, Felicity Norrie, MLS(ASCP). The following were identified from skin scrapings from a resident of a skilled nursing facility. Identification?

Monday, November 11, 2019

Case of the Week 568

This week's case is from Old One - illustrated by him and animated by his son. It features an arthropod that measures a few millimeters in length.
See it in action HERE!

Sunday, November 10, 2019

Answer to Case 568

Answer to Parasite Case of the Week 568: Pseudoscorpion or false scorporion, not a human parasite.

This fun little arthropod is occasionally submitted to the clinical laboratory for identification, and may be mistaken as a true scorpion. While both scorpions and pseudoscorpions are arachnids, pseudoscorpions are very small (1 cm or less in length) and lack a tail with a stinger. As sylvie g and Santiago note, pseudoscorpions can occasionally be found in the house, but they don't bite or sting humans, and instead feed on other small arthropods such as booklice.

Thanks again to Old One and his son for the donation of the cool animated illustration.

Tuesday, November 5, 2019

Case of the Week 567

This week's case is from Idzi Potters and the Institute of Tropical Medicine, Antwerp. The following object was seen in a concentrated stool specimen from a 3-year-old toddler with diarrhea (40x objective). It measures 45 micrometers in greatest dimension. Identification?

Monday, November 4, 2019

Answer to Case 567

Answer: Hymenolepis nana egg.
As many of you pointed out, this eggs beautifully demonstrates the filaments arising from the 2 poles of the inner membrane (arrow heads, below image). You can't make it out here, but there are 4-8 of these filaments arising from each pole. You can also nicely see the hooks of the 6-hooked oncosphere:
Some of you may know that humans become infected with this parasite when they ingest infected arthropods. As Sam mentioned, children are a common host - likely due to their tendency to put things in their mouth. Adults can also become infected as Blaine reminds us in his poem:
There once was a chap from Indiana
who with his cereal enjoyed a banana
but with the cereal he did eat
he received an unexpected treat
The cestode known as Hymenolepis nana!

If you do an internet search for "oatmeal" and "bugs," you will find multiple consumer complaints (and some nice YouTube videos) to explain the cereal reference.

Importantly, infection via ingestion of eggs shed in stool (autoinfection or from another person) is also possible, making this a common intestinal cestode infection worldwide.