The Egg Production of Ascaris lumbricoides

Abstract

The daily egg production for several different species of parastic worms has been estimated by a comparison of the number of worms obtained by treatment with the egg output as determined by the dilution egg count. By this method Stoll (1923) obtained a figure of about 9,000 eggs per day for a female of Necator americanus and Sweet (1924) and Cort, Stoll and Grant (1926) estimated the daily output of a female of Ancylostoma duodenale to be several times as large. For Fasciolopsis buski Stoll, Cort and Kwei (1927) have given an estimate of a daily output of about 25,000 eggs per worm. Faust and Khaw (1926) reported that the number of eggs produced by Clonorchis sinensis depended on the kind of host. For infestations in the cat their estimate was 2,400 eggs per day per worm, for the guinea pig 1,600, and for the dog 1,100. An egg output much higher than for any of these species would be expected for Ascaris lunibricoides, since these worms are of such large size and contain so many eggs in their uteri. Cram (1925) has recently estimated that the number of eggs in a single female ascaris may be as high as 27,000,000. We were, therefore, to some extent prepared for the high egg production figures obtained for this parasite from the study of two cases in which one of us (Brown) was able to make an egg-worm correlation in Panama.