This research will conduct a population-based field studies to determine whether the relative cost and efficacy of semi-annual versus annual administration of MDA using DEC (6 mg/kg body weight) plus ALB 400 mg (for all individuals regardless of weight) will be more successful in elimination of LF and reduction in the burden of soil transmitted helminth (worm) infections. The study involving participation of human subjects is observational in nature, uses drugs that are the standard approved treatment for LF in PNG and elsewhere in the Pacific and Asia, and does not involve administration of drugs by the investigators. Diagnosis of LF and administration of anti-LF drugs will be the responsibility of those authorized by the PNG Department of Health to perform this activity.