[Cutaneous changes induced by a dose of DEC in rodents with skin microfilaria: relevance of these phenomena for understanding the Mazzotti reaction and the pathogenesis of human onchocerciasis].

A single dose of DEC was given to Lemniscomys striatus parasitized by Monanema martini. The histopathological analysis of ear-lobe skin sections shows: a massive escape of microfilariae from the lymph capillaries, a major vascular exudative reaction with edema and diapedesis of blood cells. This inflammatory process leads to the destruction of the extralymphatic microfilariae and it induces a subacute and chronic dermatitis at the 7th day. These findings explain the pathogenesis of Mazzotti reaction during treatment of human onchocerciasis. The use of DEC produces precisely the factor that is responsible for the severity of the human disease: inflammatory reactions around the extralymphatic microfilariae.