Filaria Dance Sign (FDS) on Ultrasonography of a Patient with Filariasis

 

The dance sign is an undulating movement seen in adult worms as they wiggle about inside of dilated lymphatics ("worm nests") or onchocercal nodules.

 

Requirements: high resolution ultrasonography

 

Types of filariasis where reported:

(1) Wuchereria bancrofti

(2) Onchocerca volvulus

 

Uses:

(1) noninvasive diagnosis of a patient with filariasis, especially when asymptomatic

(2) monitoring the response of the adult worm (macrofilaria) to chemotherapy

(3) detecting adult worms in unexpected locations

(4) guiding fine needle aspiration of sites to confirm microfilaria

 

Not useful for:

(1) determining the species of the filaria

(2) monitoring the level of microfilaria in the blood after chemotherapy