Quantitative variability of nematode egg counts in faeces: a study among rural Kenyans

As part of an investigation of intestinal parasitic infections of rural Kenyan people, a study was undertaken to examine variation in faecal egg counts and to assess the sensitivity of the ether sedimentation technique of faecal processing in the diagnosis of helminth infections. Three faecal samples a day were collected for five consecutive days from 10 men known to harbour a total of 23 nematode infections of Ascaris lumbricoides, Trichuris trichiura and hookworm. Considerable variation in egg counts was encountered among faecal samples collected from the same stool, as well as over the five day period. Some possible causes of this variation are discussed, especially in relation to a high fibre diet. The technique was found to be about 95% effective in detecting an infection.