The standard regimen for elimination of lymphatic filariasis (LF) in PNG is annual administration of two drugs at the same time. The two drugs are called "DEC" (Diethylcarbamazine, 6 mg/kg body weight) and "ALB" (Albendazole 400 mg for all individuals regardless of weight), which are given one time per year for five to seven years with the aim to interrupt transmission that occurs through local mosquito vectors. These drugs kill the larval forms of the parasite in the blood that are necessary for continuing transmission of infection by the mosquito vector. The two drugs were previously thought to have little effect on adult worms, the stage of the parasite which is responsible for production of the larval forms that appear in the blood of infected people. Recent data, however, suggest that DEC and ALB can kill or render adult worms unable to produce the larval forms (sterilization). Therefore, giving these drugs twice per year for three consecutive years may increase the rate of killing or sterilizing of adults worms over regimens that involve administration of the same drugs only one time per year. The overall goal of this research is to compare the anti-parasite activity of DEC plus ALB given one time per year, the current standard for MDA to eliminate LF, to DEC plus ALB given two times per year (at 6-month intervals) in order to reduce the total duration and cost of MDA to eliminate LF in PNG. Adults (18 years and older) and minors (age 5 to 17 years) will be invited to participate in this study. Study participants will be asked to give finger stick blood samples to check LF infection status and stool samples to determine how well the drugs eliminate intestinal worm infections. Sampling will be done by repeated cross-sectional surveys in the same communities, but not necessarily the same persons, one time per year over a 3-year period. As part of the annual treatment infection surveillance the study team will also collect demographic data (place of residence, family relationship, age, use of bed nets), history of swelling of the arms and legs (elephantiasis), scrotal swelling (hydrocele), acute filarial fever accompanied by extremity swelling, and history of prior treatment for LF.