TREATMENT OF HUMAN MANSONELLA-STREPTOCERCA INFECTION WITH IVERMECTIN

We studied the short-term effects of a single dose of 150 mu g/kg body weight ivermectin on Mansonella streptocerca in an area endemic for s treptocerciasis, but not for onchocerciasis, in western Uganda. Six an d 12 days after treatment no microfilariae (mf) were found in the skin of 53 out of 96 mf carriers living in 3 villages, and the geometric m eans of the mf densities of remaining mf carriers were only 33-40% of pretreatment levels. This reduction of mf density was highly significa nt (P<0.0001). Immunohistological examination of skin biopsies showed degenerated and disintegrating mf surrounded by activated eosinophils (positive for activated cationic protein), macrophages, and neutrophil s (positive for myeloperoxidase and defensin) on day 6 after treatment . Remarkable was the invasion of young, LI protein-positive macrophage s and the release of neutrophil defensin as signs of acute inflammatio n. We conclude that ivermectin has a strong microfilaricidal activity against M. streptocerca. Common adverse effects were increased pruritu s and acute papular dermatitis in 45% of 86 mf carriers on day 6 after treatment. No serious adverse side-effects were noticed in about 700 treated persons.