Ultrasonographic diagnosis of subclinical filariasis.

Asymptomatic persons with lymphatic filariasis may harbor microfiliariae in the circulation, and despite the lack of symptoms, these patients may have occult pathologic lesions and renal abnormalities. Earlier investigators have shown that it is possible to detect live adult filarial worms and dilation of lymphatic channels with ultrasonography. It is also possible to assess response to therapy. Using sonography, we detected twirling motions in dilated lymph channels and characteristic sonographic findings associated with presence of adult filariae. On follow-up examination we also found evidence of loss of worm activity after chemotherapy.