Sunday, October 31, 2021

Answer to Case 659

Answer to the Parasite Case of the Week 659: Onchocerca volvulus adult worms and microfilarie. 

If you didn't already see it, check out the whole slide scanned image HERE.

In this case, you can see a large subcutaneous nodule containing the adult worms (each female with  a characteristic "double barrel" uterus) and microfilariae being released into the surrounding skin. 

The microfilariae are the primary source of disease, as they crawl through the skin causing intense itching and inflammatory changes. They also go to the eye and cause irreversible blindness. The latter is the reason that infection is called "River Blindness". Infection is transmitted through the bite of infected black flies (Simulium sp.) which breed in fast flowing waters.


Unknown said...

I have this right now I believe.

Unknown said...

I need help. Can't get treatment.

Bernardino Rocha said...

Once again the explanation is wonderfully eloquent. Another interesting feature of these parasites is the relationship of endosymbiosis with the bacteria Wolbachia sp. required for larval development and adult fertility and viability, with possible implications for the pathogenesis of filariasis.

Anonymous said...

Thank you Dr. Pritt for this very educational as well as enigmatic case. For some reason I could not get the well defined picture as the one you give in your answer, I will need to work on this. Just very happy to guess it right.
Florida Fan