Search

To obtain high-resolution radionuclide lymphoscintigraphic images of affected limbs in persons with both symptomatic and asymptomatic filarial infection, 36 volunteers were recruited from a Wuchereria bancrofti-endemic area of Recife, Brazil, for a prospective, controlled analysis. Subjects were stratified after determination of serologic and clinical determinants of filarial infection status. Widespread lymphatic abnormalities were found in clinically asymptomatic microfilaremic persons, who had been assumed to have infection but not disease. All patients with clinical manifestations of lymphatic pathology and marked abnormalities. No correlation was found between clinical findings and actual lymphatic function as demonstrated by lymphoscintigraphy. The initial diagnosis of lymphatic filariasis, whether asymptomatic or symptomatic, is based on nonimaging laboratory criteria. After diagnosis, lymphoscintigraphy is a valuable tool for initial assessment of any lymphatic damage. Changes in strategies for therapeutic interventions in asymptomatic microfilaremic persons, who are not usually aggressively treated, may be warranted.

Despite many millions of doses administered over the past 40 years, basic and crucial issues regarding the use, mode of action, and effectiveness of diethylcarbamazine (DEC) in many clinical situations remain unresolved. To directly investigate whether the well-known microfilaricidal and macrofilaricidal actions of DEC actually result in subsequent improvement in existing damage to lymphatic vessels or lymph nodes, 29 study subjects in Recife, Brazil were stratified into three groups according to the severity of clinical manifestations of lymphatic insufficiency. After baseline radionuclide lymphoscintigraphy was performed, subjects were treated with two courses of DEC separated by at least a six-month interval and then rescanned one year after the baseline scan. A side-by-side comparison of images obtained at baseline with those obtained at follow-up in 13 asymptomatic microfilaremic individuals, six individuals with filarial fever, and in 10 individuals with chronic pathology demonstrated essentially unchanged lymphatic morphology in all but one individual whose disease actually progressed in the face of therapy. We conclude that two 12-day treatment courses of DEC did not have a demonstrable direct or indirect effect on existing structural damage to the lymphatic system even in those individuals with preclinical disease.