Bancroftian filariasis in Egypt: Visualization of adult worms and subclinical lymphatic pathology by scrotal ultrasound

The purpose of this study was to explore the value of scrotal ultrasound as a means of evaluating Bancroftian filariasis. Color Doppler ultrasound exa minations were performed to look for subclinical hydroceles and motile adul t filarial worms (dancing worms) in dilated lymphatics. Sixty-one male subj ects from a filariasis-endemic area in Egypt were studied including 19 clin ically normal microfilaria (MF) carriers (seven with dancing worms and eigh t with subclinical hydroceles), 13 MF-negative subjects with positive filar ial antigen test results (three with dancing worms and seven with subclinic al hydroceles), 22 exposed subjects with no MF and negative antigen test re sults (no dancing worms, four subclinical hydroceles), and seven subjects w ith clinical filariasis (no dancing worms, seven hydroceles). Thus, all men tested with clinical filariasis and most clinically normal subjects with e ither microfilaremia or filarial antigenemia had abnormal ultrasound examin ation results. Ultrasound findings often changed after therapy with diethyl carbamazine, with disappearance of dancing worms and development of new scr otal calcifications or hydroceles. This study confirms the value of scrotal ultrasound as a means of noninvasively visualizing adult filarial worms an d assessing subclinical lymphatic damage in Bancroftian filariasis.