Loa loa: the use of a blood cell separator to reduce microfilaraemia before specific chemotherapy.

Three years after returning to the U.K. a 58-year-old British engineer, who had worked in the Nigerian oilfields for 24 years, was found to have Loa loa. His midday microfilarial count ranged between 12 X 10(6) and 16 X 10(6) parasites per litre. Before starting treatment, I litre of leucocyte/platelet-rich plasma was removed by means of a blood cell separator. Six intermittent cycles of blood separation were performed during a single 4-h session around midday in order to coincide with the period of maximum microfilarial presence in the peripheral circulation. This resulted in a 50% reduction of the microfilaraemia. Where facilities for blood cell separation are available, this procedure, together with appropriate chemotherapy, should be particularly beneficial in the management of heavy filarial infections.