Intra-specimen and day-to-day variations of Fasciola egg counts in human stools

Intra-specimen and day-to-day variations of Fasciola egg counts in stools were investigated for 16 cases of established fascioliasis. For each case six Kato slides from a single stool sample were examined daily for 5 consecutive days. The results indicated the presence of significant intra-specimen variations in more than one-third of the examined series, while the inter-specimen variation was almost negligible. The sensitivity of the Kato-Katz test for diagnosing Fasciola infection with three Kato slides from the same specimen or on different days ranged from 96.0%-99.1%. The examination of three Kato smears from a single stool specimen, which is more feasible in field studies, would give an accurate diagnosis of fascioliasis. Used as such, the Kato-Katz technique is highly sensitive in the diagnosis of fascioliasis.