Factors Associated with Wuchereria bancrofti Microfilaremia in an Endemic Area of Mali

Although ( ), the causative agent of lymphatic filariasis, is endemic throughout Mali, the prevalence of microfilaremia (Mf) can vary widely between villages despite similar prevalence of infection as assessed by circulating antigen. To examine this variation, cross-sectional data obtained during screening prior to an interventional study in two neighboring villages in Mali were analyzed. The overall prevalence of , as assessed by CAg (circulating antigen), was 50.3% among 373 participants, aged 14-65. Mf-positive and negative individuals appeared randomly distributed across the two villages (Moran's I spatial statistic = -0.01, Z score =0.1, P>0.05). Among the 187 subjects positive for CAg, 117 (62.5%) had detectable microfilaremia ( Mf) and 64 (34.2%) had detectable microfilaremia. The prevalence of microfilaremia was 73.4% in the Mf-positive group (as compared to 56.9% in the Mf-negative group; p=0.01), and median Mf load was increased in co-infected subjects (267Mf/ml vs 100 Mf/ml; p