Setting characteristics and treatment scenarios for simulations.

For each combination of the listed factors, we estimated the probability of elimination (zero prevalence of infection) 50 years after the last mass treatment, based on 1,000 repeated simulations in ONCHOSIM.aSeasonality of fly biting rates was assumed to be proportional to the seasonal pattern observed in Asubende, Ghana [19]; the monthly biting rates (January–December) were assumed to be 104%, 91%, 58%, 75%, 75%, 66%, 102%, 133%, 117%, 128%, 146%, and 105% times the average monthly biting rate.bCMFL values of 5 and 10 mf/ss are representative for APOC regions that were mesoendemic before the start of control (pre-control mf prevalence between 40% and 60%); the higher values of CMFL are representative for hyperendemic areas (mf prevalence>60%)[10]. We did not simulate areas with lower endemicity, where the expected duration of mass treatment is shorter.cLow variation in exposure was combined with all possible values for pre-control CMFL. High variation in exposure was only combined with pre-control CMFL of 5 and 10 microfilariae per skin snip; assuming that for highly endemic areas individual variation in exposure to fly bites is not very high because of the multitude of flies (i.e. everyone is bitten very often).dSimulated mass treatment rounds were scheduled on 1st of July (annual), just prior to the annual seasonal peak in fly biting rate, or additionally on the 1st of January (6-monthly treatment) and the 1st of April and 1st of October (3-monthly treatment). If the mass treatment program was assumed to switch from annual (past) to 6-monthly or 3-monthly (future) treatment, the future mass treatment scenario was scheduled to start on the 1st of January of the next year (i.e. six months after the last ‘past’ treatment), or on the 1st of October of the same year (i.e. three months after the last ‘past’ treatment), respectively.eHypothetically, increasing the frequency of mass treatment might induce treatment fatigue in the population, or lead people to think that it's not so bad to skip a mass treatment round as there will be another one in the near future.fHypothetically, increasing the frequency of mass treatment might increase awareness about onchocerciasis and motivate people to participate.Setting characteristics and treatment scenarios for simulations.