[Correlation between the number of microfilaria ingested and the thickness of the peritrophic membrane of the vector in onchocercosis of the African savannah].

The fact, as previously established, that a great number of microfilariae remain trapped in the peritrophic membrane of S. damnosum, explains the low proportion of microfilariae passing into the hemocoel. However, it doesn't account for the strong "limitation phenomenon" observed in savannah. Histological analysis shows a growth of the peritrophic membrane proportionate to the number of ingested microfilariae. The microfilariae, exciting the digestive epithelium, provoke the liberation of greater quantities of peritrophic substance, thus reinforcing the peritrophic barrier.