Loa loa: a simple method for isolation of microfilariae from blood with production of antigen in extraction medium.

A simple method for isolating Loa loa microfilariae from the blood of patients is described. This involves sedimentation on Ficoll followed by migration of the microfilariae into an extraction medium. During migration the microfilariae release antigen-rich excretory or secretory products. The procedure thus yields two products: pure microfilariae and large amounts of antigen in the extraction medium.