The study population (3,200/survey) will include male and female subjects >=5 years of age living in East Sepik Province, PNG. If unexpected logistical problems should arise, other study areas have been identified in Madang Province. The proposed study area will be in the Dreikikier Rural Local Level Government (LLG, approx pop 20,000) and Gawanga Rural, LLG (approx pop 13,000). Residents of villages previously treated with MDA will not be included in the study.