FIELD-EVALUATION OF AN IMPROVED KATO-KATZ THICK SMEAR TECHNIQUE FOR QUANTITATIVE-DETERMINATION OF HELMINTH EGGS IN FECES

A new method for the quantification of helminth eggs in faeces was dev eloped, in which 7.5% nigrosin in 10% formaldehyde mixed with 5% eosin yellow in 10% formaldehyde was substituted for the malachite green so lution used in the standard Kato-Katz method. This modification reveal ed the eggs of parasites like Schistosoma mansoni, Ascaris lumbricoide s, Trichuris trichiura and hookworms distinctly. The slides made with this new technique could be accurately read within one hour. Faecal sm ears from 100 pupils in Kigungu, Entebbe, Uganda, were studied with bo th methods. The egg counts of S. mansoni, A. lumbricoides and ?: trich iura by both methods were equal. The modified method, however, showed significantly higher hookworm egg counts (p < 0.001). Hookworm eggs we re equal one hour after preparation of the slides as 16 hours after pr eparation. The intensity of infection detected was higher with the mod ified method for both S. mansoni and hookworms.