Western Africa comprises 17 countries and is endemic for all five PC-NTDs and loiasis. Most of the region is endemic for LF, or has been historically. Several countries have successfully reduced LF transmission and implement post-MDA surveillance in certain districts. Onchocerciasis occurs throughout the tropical belt covering the southern part of the region. The region is mostly free of Loiasis, although this disease occurs throughout Nigeria. All countries are affected by schistosomiasis and STH, although endemicity levels vary within and between countries.