the bancroftian filaria, a species endemic in the South Pacific islands, coastal China, India, and Myanmar, and throughout tropical Africa and northeastern South America (including certain Caribbean islands). Transmitted to humans (apparently the only definitive host) by mosquitoes, especially Culex quinquefasciatus and Aedes pseudoscutellaris, but also by several other species of Culex, Aedes, Anopheles, and Mansonia, depending on the specific geographic area. Adults are white, 40-100 mm, cylindric, threadlike worms, and the microfilariae are ensheathed, with a rounded anterior end and a tapered, nonnucleated tail; the adult worms inhabit the larger lymphatic vessels (e.g., in the lower extremities, breasts, spermatic cord, and retroperitoneal tissues) and the sinuses of lymph nodes (e.g., the popliteal, femoral, and inguinal groups, as well as the epitrochlear and axillary nodes), where they sometimes temporarily obstruct the flow of lymph and cause slight to moderate inflammation.