Friday, December 23, 2011

Case of the Week 189

Dear Readership of Creepy Dreadful Wonderful Parasites,
May you have a wonderful holiday season with friends and family! Thank you for your continued support and comments.

Here is the 'case' for this week - a simple identification:

Thursday, December 22, 2011

Answer to Case 189

Answer: Phthirus pubis, a.k.a the crab louse, or as my readers said:
"the Yuletide pubic louse", "Pthirus barbae viridis: green bearded louse", "Pine-scented pubic louse", and "Louse found in Bad Santa's trousers"

Happy 2012!
Parasite gal

Monday, December 12, 2011

Case of the Week 188

The following objects were found in the clothing of an 18 month old child. They measure approximately 3mm in length.


By manipulating them with a wooden applicator stick, the following was expressed out of these objects (CLICK ON IMAGES TO ENLARGE):

(100x original magnification)


(400x original magnification)



Thanks to Emily in my lab for these beautiful photos!

Sunday, December 11, 2011

Answer to Case 188

Answer: Proglottids and egg packets of Dipylidium caninum, the double-pored dog tape worm.

This small tape worm is acquired through ingestion of infected Ctenocephalides spp. fleas, prompting one of my readers to ask if the child got infected by ingesting the specimen from the previous case of the week! Another reader, MicrobeMan, had a similar inquiry "Was it merely coincidental that you posted Ctenocephalides last week? Regardless, it's very appropriate, seeing as that both adult C. canis and C. felis can carry the cysticercoid form of D. caninum to people."

To answer these questions - it was actually a complete coincidence that we happened to have a Ctenocephalides flea and D. caninum proglottids submitted to my lab in such a short time period of time, and I wasn't really considering the coincidence when posting these 2 cases. So good pick up for those of you who noticed!

I like this case because it has several classic features which allow for definitive identification. The small "rice grain" sized and shaped proglottids are classic, and the egg packets that were expressed from the proglottids are diagnostic, despite being immature. Note that the material surrounding the eggs is very granular, which is something I've seen frequently when eggs are prematurely expressed from the proglottids, rather than being released naturally. So don't let that deter you from making a diagnosis if the other characteristic features such as egg packets and hooklets inside of egg-like structures are present

Monday, December 5, 2011

Case of the Week 187

Since I am at the ASTMH annual meeting at the moment, I will keep this case short and sweet:

The following was submitted for identification to the clinical parasitology laboratory. It was difficult to get it to hold still, since it was jumping between lids of a closed petri dish. It measures approximately 2 mm in length. (CLICK ON BOTTOM RIGHT OF MOVIE TO ENLARGE)

Identification?
video

Sunday, December 4, 2011

Answer to Case 187

Answer: Flea

Everyone who wrote in got this correct, despite the fact that the flea wasn't really staying still. We eventually took Blaine's advice and killed it (by placing it in ethanol). We then mounted it on a slide and got a much clearer picture of the flea, showing the genal and pronotal combs that are characteristic for Ctenocephalides species:



The dog and cat fleas (Ctenocephalides canis and C. felis respectively) can be further differentiated based on the shape of their head and "tooth" length of the genal comb.