Rapid method for the purification of viable microfilariae from nodules of Onchocerca volvulus by Percoll gradient centrifugation.

Microfilariae of O. volvulus were purified from dissected nodules by centrifugation on discontinuous Percoll density gradients. Nodules were used freshly or after cryopreservation in liquid nitrogen. Highly purified and motile microfilariae were recovered from a layer of a density of 1.090 g/ml. The isolated microfilariae retained their motility up to 3 days when cultured in vitro.