Dear Readers,
Welcome to Filariasis Month! We will actually have TWO months of filariae for you as there are so many to cover and so many beautiful cases by Idzi and the Institute of Tropical Medicine, Antwerp.
Idzi and I thought that we should start out with an 'easy' one. The following objects were seen on a blood smear from a patient living in Gabon. They are approximately 250 micrometers long. What is your identification? Bonus question: what additional laboratory test is important for guiding treatment?
Giemsa stained blood films:
12 comments:
This small, very mobile, unsheathed filariae appears to me to be Dipetalonema perstans, alias mansonnela perstans, a non-pathogenic human filariae common in Gabon. This filarial is present in the blood day and night.
To guide treatment, it is essential to verify the absence of coinfection with Loa-Loa to avoid the occurrence of serious reactions. This being that D. perstans is non-pathogenic it is possible to abstain.
I am a novice at these but will venture a guess despite no measurements being provided: Wuchereria bancrofti. My choices are, based on the location (Africa) and source (blood), are Wuchereria, Loa loa, and Mansonella perstans. The nuclei do not extend down to the end of the tail. They should in the other two but not Wuchereria. In picture 2 of this challenge, it looks like there might be a sheath, but in the Hematoxylin stain, I don't see a sheath, which leaves me room for some doubt on my guess. For the second part of the question, the patient should be checked for Loa loa and Onchocerca volvulus before treating with DEC.
The first consideration when dealing with microfilaria is the presence or absence of a sheath, the second is geographic location and third the distribution of the nuclei. In this case, I had a hard time finding a sheath and would eliminate Loa loa, Wucheria and Brugyia spp. all together.
Going with Nema’s comments, I found more literatures on the Internet about the dangers involved in co-infection of Dipetalonema perstans and Loa loa.
Thank you Nema for shedding a light on the subject.
Florida Fan
Question: How many blood smears does one have to check to find/eliminate this sort of parasite?
A tip: especially in the carazzi stain, note the thickness of the microfilaria and zoom in on the tail! 😉
Los loa mmf has sheeth and has nuclei to the end of lovely tail. Thank you Doctor.
I’m the anterior Dr. @MercedeSubirats thnks a lot
Wuchereria bancrofti.
Check for co-infection with loiasis as treatment for that is dependent on microfilarial load.
Idzi, Thanks for the tip. The Romans said:”In cauda venenum”. The terminal nuclei says it all.
Florida Fan
It looks like there is a sheath to me and in one of the examples looks like nuclei extend to end of sheath, also one showed 2 nuclei at end of sheath, In my humble opinion. According to AI, Brugia malayi can be found in Gabon.
Mf Loaloa because it has the unstained sheath, nuclei reach up to terminal end, patient from Africa. Additional lab test : serology test to differentiate from Wuchereria because the drug of choice is different
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