A new modified quantitative Kato-Katz thick-smear technique for the detecti
on of helminth eggs in faeces preserves hookworm eggs unaltered for a long
time, while with the classic Kato-Katz technique, they disappear after appr
oximate to 2 h in tropical climates and thus slides must be read within hou
rs after sample collection. For an independent comparison of these two labo
ratory techniques, faecal smears from 263 school children were examined in
two surveys and prevalence, intensity of infection and costs of surveys cal
culated. There was no statistical difference between the methods in detecti
ng prevalence and stratification of the sample in different classes of inte
nsity While there was no statistical difference for the arithmetic mean of
the epg for T. trichiura and only a small difference for A. lumbricoides (P
= 0.04), we observed a highly significant difference for hookworm mean int
ensities of infections (P < 0.001). From the public health viewpoint both m
ethods provided similar results, but due to its simplicity and widespread u
se the classical Kato-Katz technique remains first choice for community inv
estigation of soil-transmitted nematodes. However, the Nigrosin-Eosin appro
ach has several advantages and can be a valuable alternative in certain cir
cumstances.