Wuchereria bancrofti: the staining of the microfilarial sheath in giemsa and haematoxylin for diagnosis.

Indigenous cases of bancroftian filariasis have recently been identified in the country for the first time. The diagnosis of such infections depends on demonstrating the characteristic sheathed microfilariae of Wuchereria bancrofti in the blood. Giemsa, a stain recommended by many authors, was found to be unsuitable as the microfilarial sheath, an important distinguishing feature, does not take up the stain. In contrast, the sheath stains clearly in haematoxylin. The differences in the staining reaction of the microfilariae in the two stains is demonstrated. The need to establish the presence of the sheath is emphasized, especially since the microfilariae of Dipetalonema perstans, the widespread filarial infection in the country, are unsheathed.