The study design is repeated cross-sectional surveys examining each subject once. Some subjects may be included in more than one annual population survey, but this is not a longitudinal study. Approximately 3,200 individuals will participate per year at the beginning of the study and at years 1, 2 and 3 (a total of 4 cross-sectional surveys). The study will include both females and males 5 years of age and older who live in a LF endemic area of PNG. Subject selection will not be based on health status. The study aims to determine the relative impact and cost effectiveness of annual versus twice yearly MDA (DEC 6 mg/kg body plus Alb 400 mg for all individuals) for elimination of LF and reduction in soil transmitted helminthic infection burdens in these populations.