A rapid, simple method for isolation of viable microfilariae.

We describe a rapid, efficient method for purifying Loa loa microfilariae from blood that does not affect their longterm motility. It is based on the separation of microfilariae on a performed discontinuous Percoll gradient, followed by filtration on cellulose ester membranes. The parasite population, after isolation, is close to 100% pure, 100% viable and remains motile for at least 20 days. Recovery from original blood samples is typically around 90%. The method, because of its simplicity and minimal material requirements, could be used with up to 210 ml of blood. It also allows the isolation of Mansonella perstans microfilariae.