Participants will have routine tests to determine the specific type of filarial infection. These may include special tests of the lungs, skin or heart, depending on the type of parasite suspected. Patients with skin reactions may have a "punch biopsy" to examine a small piece of affected skin. For this procedure, an area of skin is numbed with an anesthetic and a small circular area, about 1/3-inch in diameter and 1/2-inch thick, is removed using a sharp cookie cutter-type instrument. Some patients may require bronchoalveolar lavage. For this procedure, the mouth and throat are numbed with lidocaine jelly and spray and, if needed, a sedative is given for comfort. A small plastic tube is placed in a vein to give medications. A pencil-thin tube is then passed through the nose or mouth into the lung airways to examine the airways. Salt water is injected through the bronchoscope into the air passage, acting as a rinse. A sample of the fluid is then withdrawn and examined for infection, inflammatory cells and inflammatory chemicals. (Bronchoalveolar lavage is done only if medically necessary and only on patients 21 years or older.) Once the diagnosis is established, standard treatment will be instituted with either diethylcarbamazine or ivermectin, depending on the type of infection.