Variability of egg excretion in Schistosoma mansoni infection in Ethiopia: a case report

An Ethiopian boy, aged 18 years, and heavily infected with S. mansoni (1250 eggs per gram of faeces), gave stool sample for microscopy three times a day (at 9:00 am, 1:00 pm and 4:00 pm) for 5 consecutive days. Each time two slides were prepared by the modified Kato's thick-smear technique. The maximum egg count at each examination was converted to eggs per gram of faeces (EPG). There was no significant variability (at 10% level, F-value = 0.04) in in egg counts made at different times of the day. However, the coefficient of variations between the egg counts made on different days were fairly high ranging from nearly 61% to 73% and the differences being highly significant at 10% level (F value = 4.076). The implications of this day-to-day variability of S. mansoni faecal excretion in "selected" chemotherapy in Ethiopia is discussed.