OCCURRENCE OF LIVING ADULT WUCHERERIA-BANCROFTI IN THE SCROTAL AREA OF MEN WITH MICROFILAREMIA

To determine the frequency with which living adult Wuchereria bancroft i can be detected by ultrasound in the scrotal area of men with filari al infection, we used a 7.5 MHz transducer to perform weekly ultrasoun d examinations on 100 microfilaraemic men (18-34 years old) from Great er Recife, Brazil. The peculiar pattern of movement that characterizes the adult worm image on ultrasound (the filaria dance sign) was detec ted in the lymphatic vessels of the spermatic cord in 80 men (bilatera lly in 29 men). Among 20 men with no filaria dance sign, the geometric mean microfilarial density was 68/mL, compared with 238/mL and 775/mL among those with unilateral and bilateral filaria dance signs, respec tively (P=0.0001). The lymphatic vessels of the spermatic cord appear to be a common, and perhaps the principal, site of adult W. bancrofti in men with asymptomatic microfilaraemia. Studies are needed to define the relationship between the presence of filarial worms in the scrota l area and the development of filaria-associated morbidity.