Patients admitted on this protocol will have, or be suspected of having, one of the filarial infections affecting humans. After routine clinical evaluation they will be studied in depth immunologically, and their blood cells and/or serum will be collected to provide reagents (eg., specific antibodies, T-cell clones, etc.) that will be used in the laboratory to address the broader questions of diagnosis, immunoregulation, pathology and immunoprophylaxis. Careful observations of the patients' clinical and immunologic responses to therapy will be made, as well as long-term follow-up of these changes. It is anticipated both that the patients will receive optimal clinical care for their infections and that the specimens collected from them will prove to be valuable reagents for the laboratory studies of the immunologic responses unique to filarial or other related helminth infections.