Sunday, March 17, 2024

Answer to Case 741

 Answer to the Parasite Case of the Week 741: Mansonella ozzardi

As many of you noted, we can get to an identification of Mansonella sp. by the small size (length of just 175 micrometers, and the width less than the surrounding white blood cells). There is also no visible sheath, which is supportive of the diagnosis. 

So the next question is - which Mansonella is present?? As FloridaFan mentioned, the tip of the tail is pointed rather than blunt, which leads us away from M. perstans. Also, the source is not skin snips, so M. streptocerca is unlikely. That leaves M. ozzardi by default. 

To confirm this, we would look at the tail to see if the nuclei go to the tip (M. perstans) or not (M. ozzardi). It's a bit hard to tell in this case, but if you look closely, you can see that the nuclei DON'T go to the tip of the tail. So - Mansonella ozzardi, it is!

Congratulations to those of you who were able to get to Mansonella species. The microfilariae can be hard to identify, so this is definitely advanced  parasitology!


Anonymous said...

Thanks a lot for those amazing slides. Would you mind suggesting good resources for microfilariae reference please and thank you.

ParasiteGal said...

Hi Anonymous, I'm happy to provide you with some resources! Please see my first post in this series that outlines several resources, including freely available ones:


Anonymous said...

This is the first slide I’ve seen of Mansonella. Are you able to disclose which institution found it?

ParasiteGal said...

Hi Anonymous,
thank you for writing!
These cases are all from Idzi Potters at the Institute of Tropical Medicine in Antwerp, Belgium.