Monday, January 21, 2008

Parasite Case of the Week 5

Many of you will be happy to see that there is NO arthropod in this week's case. Instead I have something a bit unusual - some movies. These are short films of what you might see in a "hot stool" - that is, one that comes fresh from the patient without any fixative. This method is commonly used in the tropics for diagnosis. Furthermore, you're bound to see questions regarding characteristic motility on Board exams and the like, so it's good to be familiar with the classic patterns.

The first movie shows the classic motion. The second movie is to demonstrate morphology. The organism in question has finally slowed down enough to allow a closer look.

Questions:
1. Identify the organism
2. State the significance of finding this organism in a stool sample.


video
Movie showing characteristic motion

video
Movie showing morphology

3 comments:

Ian said...

Is this Giardia?

Tom said...

Having only read about it, I assume this is the "tumbling leaf" motion of Giardia.

Heather said...

I disagree!! This is more what I call the "Night at the Roxbury Guys" movement--you know, the head-side-twitch to the beat of the music thing. (Don't know what I mean? Check it out here: www.youtube.com/watch?v=1ytKvEv9szg )
This is characteristic motility of Trichomonas species. If in stool, then, this would be Trichomonas hominis, and in a genital source would be Trichomonas vaginalis. T. hominis is a commensal and considered nonpathogenic, while T. vaginalis is, of course, a problem.