Encephalopathy Related to Ivermectin Treatment of Onchocerciasis in Loa loa Endemic Areas: Operational Considerations

Abstract

Miscellanea on Encephalopathies 170 EpidemiologyOnchocerciasis, also known as river blindness, is caused by a filarial nematode, Onchocerca volvulus. The adult worms lives in subcutaneous nodules within surface muscles, mainly around the pericostal and the iliac crest.There are two mains subtypes of Onchocerca volvulus, namely the forest and savanah. In the savanal infections, the nodules are mainly located on the upper part of the body, including the trunk, upper limbs and head. Ocular involvement is frequent. In the forest infections, nodules are found primarily on the lower limbs and iliac crest. Cutaneous alterations are the main manifestations of the disase.The worm is transmitted through the bite of female blackflies of the genus Simulium, which bite during the day. The fly breeds in rapidly flowing rivers and streams.Onchocerciasis is endemic in most countries in sub-saharan Africa. Isolated endemic foci are also present in the Arabian Peninsula (Yemen) and in the Americas (Brazil, Colombia, Ecuador, Guatemala, southern Mexico, and Venezuela). An estimated 17 million people are infected worldwide.