title: Evaluation of the Kato-Katz thick smear and formol ether sedimentation techniques for quantitative diagnosis of Schistosoma mansoni infection.
abstract: The present study compared the Kato-Katz thick smear and formol ether sedimentation techniques in the diagnosis of Schistosoma mansoni infections. A stool specimen was collected from 915 individuals representing a high prevalence community (63.3%) and from 471 individuals representing a relatively low prevalence village (40%). The overall sensitivity of a single Kato-Katz smear was 70.8%, and it increased with each additional slide to reach 91.7% on examining four smears. However, the sensitivity was 83.3% when using the formol ether sedimentation technique. In terms of quantitative analysis, the geometric mean egg count was 94 eggs per gram (epg) of stool by two Kato-Katz smears, and 43 epg by the sedimentation technique. This means that more than 50% of eggs were missed when using the sedimentation technique, a fact that should be taken into consideration when relating infection level with morbidity.
authors.affiliation: Department of Tropical Health, High Institute of Public Health, Alexandria University, Egypt.
authors.forename: A
authors.initials: A
authors.lastname: Ebrahim
authors.forename: H
authors.initials: H
authors.lastname: El-Morshedy
authors.forename: E
authors.initials: E
authors.lastname: Omer
authors.forename: S
authors.initials: S
authors.lastname: El-Daly
authors.forename: R
authors.initials: R
authors.lastname: Barakat
mesh_terms: D000818:Animals; D003430:Cross-Sectional Studies; D019937:Diagnostic Techniques and Procedures; D004986:Ether; D005243:Feces / Q000469:parasitology*; D005557:Formaldehyde; D006801:Humans; D010270:Parasite Egg Count; D012550:Schistosoma mansoni / Q000302:isolation & purification*; D012555:Schistosomiasis mansoni / Q000175:diagnosis*; D012680:Sensitivity and Specificity
chemical_list: D004986:Ether; D005557:Formaldehyde