Safety and Efficacy of Annual or Biannual Doses of Moxidectin or Ivermectin for Onchocerciasis

Inclusion Criteria: * Provision of written informed consent, or assent with parental or guardian written consent. * Mean ≥ 10 O. volvulus microfilariae/mg skin, determined by four skin snips * Living in a village selected for the study. * Age ≥ 12 years. * All female participants of childbearing potential must commit to the use of a reliable method of birth control for the duration of treatment and until 3 months after completion of dosing with investigational product. Exclusion Criteria: * Pregnant or breast-feeding. * Any concurrent condition that, in the opinion of the Investigator, would preclude evaluation of response to treatment or would pose undue risk to the participant's health. * Has received ivermectin, oral diethylcarbamazine (DEC) or doxycycline (for \> 2 weeks) within 6 months of Baseline. * Has received treatment with an investigational agent within the last 30 days (or 5 half-lives, whichever is longer) prior to Baseline. * Known or suspected allergy to ivermectin or moxidectin or their excipients. * Self-reported planned or ongoing activities within the study period that would make it unlikely that a participant will be available for all planned treatment rounds and follow-up examinations. * Weight \> 88 kg. * Infection with Loa loa.