Longitudinal study in Nwa confirms absence of M. perstans infection (a) Prevalence and (b) mf intensity in Nwa health district (10 communities) prior to IVM therapy (0 MDA; n = 1,029) and after 8 years of MDA programme (8 MDA; n = 1,329). In 2000, only 2 individuals positive and in 2013, 6 individuals were M. perstans positive. (DOCX 167 kb)