Comparison of annual and biannual community-directed treatment with ivermectin (aCDTI, bCDTI) versus annual community-directed treatment with moxidectin (aCDTM) in areas where control has not been previously implemented. The green, blue and red bars correspond to a pre-control endemicity level of 40%, 60%, and 80% microfilarial prevalence, respectively. The aCDTI, bCDTI and aCDTM strategies are indicated by solid, dashed and dotted bars respectively. Error bars represent the results of varying the provisional operational thresholds for treatment interruption followed by surveillance (pOTTIS) by adding or subtracting 0.5% (i.e. 0.9% or 1.9% microfilarial prevalence). Results shown assume a therapeutic coverage of 80%; a proportion of systematic non-compliers of 0.1%; perennial transmission, and a 7% per dose (cumulative) reduction in microfilarial production of female adult worms. A discount rate of 3% was applied to the costs. *pOTTIS (1.4% microfilarial prevalence) not attained within the 50-year time horizon and percentage of costs calculated based on costs of 50 years of aCDTI. † Costs do not include value of the (donated) drugs.