Comparison of a digestion-sedimentation technique with the Kato-Katz technique in the detection and quantification of S. mansoni eggs in light to moderate infections

Abstract

A comparison between a digestion-sedimentation technique (DST) and the Kato-Katz thick smear technique (KKT) in the detection and quantification of Schistosoma eggs in stool was carried out in 551 subjects. Specimen were collected one or two years after treatment with praziquantel from subjects living in a schistosomiasis endemic area of Mali. One hundred infections missed by the KKT were detected by the DST. Conversely, 35 infections missed by the DST were detected by the KKT (88 % were light infections). More subjects were classified as lightly infected by the DST (p < 10-3) and more subjects were classified as moderately infected (101-400 epg) by the KKT (p = 0.02). The KKT produced higher counts than the DST among the youngest age group which was also the most infected. The principal advantage of the DST over the KKT was its better sensitivity to detect light infections resulting from a larger amount of stool processed.