 The purpose of this study is to check blood samples for lymphatic filariasis to determine whether the recent Program to Eliminate Lymphatic Filariasis was successful in controlling lymphatic filariasis in areas of Egypt. Volunteers will participate in a health assessment program carried out by Ain Shams University and approved by the Egyptian Ministry of Health and Population. This program includes a brief interview and laboratory tests to detect worm parasites in participants blood. Volunteers and family members found to have worms in their blood will be referred for treatment. This study will provide early detection of this parasitic infection and referral for prompt treatment in order to prevent spread of the infection to others. Approximately 23,500 people, 6 years of age and older, will participate per year. Study participants will include people living in areas of Egypt that are known to have the filariasis parasite. Volunteers will participate for up to 2 years. 