Daily egg production of Ascaris lumbricoides: the distribution of eggs in the faeces and the variability of egg counts

Abstract

SUMMARYFifteen children aged from 6 to 12 years who were infected with Ascaris lumbricoides were selected for the study. The number of eggs/g (e.p.g.) of stool was determined using Beaver's direct smear technique, Stoll's dilution egg count technique and Katz's modified thick smear technique. Beaver's direct smear method consistently gave a higher e.p.g. than the other two methods. Results of this study show that Katz's modified thick smear technique was the best of the three methods used. The e.p.g. depends on several factors: the amount of stool passed daily, the concentration of eggs within a stool sample, the daily egg output, the worm load, the age of the worm and the technique used for determining the egg load. The daily average egg output/female A. lumbricoides was estimated to be 238722 (range 134462–358 750) with an average e.p.g. of 3540. The estimation of worm load based on egg count is useful in determining the intensity of infection in an individual. The male/female worm ratio was estimated to be 1: 1·4.