Periodicity of Wuchereria bancrofti microfilariae in south western Ethiopia

As part of a clinical and epidemiological study of lymphatic filariasis in southwestern Ethiopia the microfilarial density in the blood of two male and two female volunteers from the village of Ketch (near the town of Gambella) was determined every four hours for a 24-hour period using the counting chamber technique. In the blood of the volunteers the majority of the microfilariae appeared between 20 and 04 hours with peak at 24 hours (range at peak time + 3060-3560 mf/ml blood) depicting a nocturnal periodicity of circulating Wuchereria bancrofti microfilariae. This has important implications for the diagnosis, monitoring and transmission of lymphatic filariasis in the area.