African health sciences

Substitution of malachite green with nigrosin-eosin yellow stain in the Kato-Katz method: microscopical appearance of the helminth eggs.

PMID 17604523


The Kato-Katz thick smear technique is the standard technique recommended by the World Health Organisation for the quantitative diagnosis of Schistosoma mansoni and other intestinal helminth infections. The major problem of the technique is that a few hours after the preparation of slides hookworm eggs over clear and disappear due glycerin. To illustrate clear visibility of different helminth eggs microscopically in Odongo-Aginya method, substitution of malachite green with 7.5% nigrosin in 10% formalin and 5% eosin in 10% formalin. Measured, strained stool specimen was stained with mixture of nigrosin/eosin and covered with cellophane cover slips. The prepared slide was examined immediately microscopically. Slides prepared with Odongo-Aginya method can be examined immediately or later without compromising the visibility of parasite eggs and larvae. Hookworm eggs remain visible for a long time. The present publication shows microscopic appearance of the helminth eggs using the Odongo-Aginya modification.