Sunday, November 29, 2015

Case of the Week 374

This lovely little family was found on a 20 year old male. Thanks to Florida Fan for donating this case!  Identification?

Monday, November 23, 2015

Case of the Week 373

The following structures were found in stool.  They measure approximately 60 micrometers in greatest dimension. Identification?

Sunday, November 22, 2015

Answer to Case 373

Answer: pinworm eggs - with a newly emerging larva. Kudos to Felicity in my lab for catching this worm in action!

Note the range of eggs seen here, including a classic oval/elliptical eggs with flattened side, an egg containing a larva, and lastly, the emerging larva.

And here's a poem from Blaine!

So many nematodes in the gut, it’s hard to tell which is which
But Enterobius vermicularis fulfills a particular niche
For she likes to come out at night
And oviposit at the site
That is sure to make your booty itch!

Sunday, November 15, 2015

Case of the Week 372

Several objects were removed from a foot wound of a 70 year old woman. Representative photos of one of these objects is shown below. Identification?

Saturday, November 14, 2015

Answer to Case 372

Answer: Musca domestica (common housefly) larva

Unlike obligate parasites such as Dermatobia hominis, Musca domestica is a cause of accidental myiasis. While M. domestica larvae are usually found in nutrient rich organic material such as compost and manure, they can occasionally infest human tissues. The adult flies can also serve as a mechanical vector for infectious agents including bacteria, viruses and parasites.

The CDC has an excellent online reference for identifying medically important flies that you can access HERE. As you can see from the identification key, fly larvae are identified by a number of features including their overall shape and characteristics of their posterior spiracles. The line drawing of the M. domestica spiracles is shown below, next to the photograph from this case for this comparison.

Tuesday, November 10, 2015

Case of the Week 371

This week's case was generously donated by Dr. Zhenwen Zhou, MD, from the Department of Laboratory Medicine at Guangzhou Women and Children's Medical Center, Guangzhou Medical College, in Guangzhou, People's Republic of China.

The patient is a middle-aged man who found the object below in his stool. He reports eating rare beef approximately 2 months earlier.


Sunday, November 8, 2015

Answer to Case 371

Answer: Taenia species tapeworm segment.

The segment shown is notable for the fact that it is still moving (!) as well as the fact that the proglottids are longer than they are wide. The latter feature, in addition to the large size of the worm, supports an identification of Taenia species (as compared to Diphyllobothrium spp., Dipylidium caninum, and Hymenolepis spp. Unfortunately, we are not given any additional morphologic features that would allow us to determine which Taenia species is shown (such as the uterine branching pattern or scolex). However, Florida Fan and other readers correctly note, that the history of eating undercooked beef supports the supposition that this is T. saginata. In comparison, Taenia solium and Taenia asciatica are acquired by ingesting undercooked pig (muscle, or in the case of T. asciatica, liver and possibly other organs).