title: Comparison of sensitivity and faecal egg counts of Mini-FLOTAC using fixed stool samples and Kato-Katz technique for the diagnosis of Schistosoma mansoni and soil-transmitted helminths.
abstract: Accurate diagnostic tools for human helminthiasis are crucial for epidemiological surveys, improved patient management, and evaluation of community-based intervention studies. However, the diagnosis of intestinal schistosomiasis and soil-transmitted helminthiasis heavily relies on stool microscopy using the Kato-Katz technique, which has a low sensitivity. The Mini-FLOTAC method is an alternative microscopy-based technique, but its diagnostic performance using sodium acetate-acetic acid-formalin-(SAF)-fixed stool specimens has not been validated. The fixation of stool samples for later examination in a laboratory may reduce logistical and financial barriers of prevalence surveys by not requiring field laboratories. We compared the diagnostic accuracy of the Kato-Katz technique using fresh stool samples with the Mini-FLOTAC technique, employing matched stool samples that were fixed in SAF. Three consecutive stool samples from 149 school-aged children in Côte d'Ivoire were subjected to quintuplicate Kato-Katz thick smears examined on the same day. From the remaining stool, approximately 2g was fixed in 10ml of SAF for about 3 months, and then subjected to the Mini-FLOTAC method, using two flotation solutions (FS2 and FS7). The combined results of multiple Kato-Katz and Mini-FLOTAC readings revealed prevalences of Schistosoma mansoni, Trichuris trichiura and hookworm of 99.3%, 72.5% and 7.4%, respectively. Employing a Bayesian latent class analysis to estimate the true sensitivity of the diagnostic approaches, the sensitivity of Mini-FLOTAC using FS2 was 50.1% (95% Bayesian credible interval (BCI): 30.9-70.2%) for hookworm and 68.0% (95% BCI: 34.9-93.5%) for T. trichiura. When applying Mini-FLOTAC using FS7, the sensitivity was 89.9% (95% BCI: 86.9-97.4%) for S. mansoni, 37.2% (95% BCI: 17.2-60.6%) for hookworm and 67.7% (95% BCI: 33.0-93.0%) for T. trichiura. The specificity ranged from 80.1-95.0% in all Mini-FLOTAC tests. Mini-FLOTAC revealed higher arithmetic mean faecal egg counts (FECs) than the Kato-Katz technique. We found a significant correlation in FECs between Kato-Katz and Mini-FLOTAC for S. mansoni and T. trichiura. We conclude that Mini-FLOTAC shows reasonable diagnostic accuracy when using stool samples fixed in SAF for 3 months, and may be an alternative to multiple Kato-Katz thick smears.
authors: Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 02 BP 770, Abidjan 02, Côte d'Ivoire; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan 01, Côte d'Ivoire; Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland; University of Basel, P.O. Box, CH-4003 Basel, Switzerland. Electronic address: couljeanvae@yahoo.fr.
authors: Jean T
authors: JT
authors: Coulibaly
authors: Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 02 BP 770, Abidjan 02, Côte d'Ivoire.
authors: Mamadou
authors: M
authors: Ouattara
authors: Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland; University of Basel, P.O. Box, CH-4003 Basel, Switzerland; Institute of Medical Microbiology and Hygiene, Saarland University, Kirrberger Straße, Building 43, 66421 Homburg/Saar, Germany.
authors: Sören L
authors: SL
authors: Becker
authors: Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
authors: Nathan C
authors: NC
authors: Lo
authors: Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland; University of Basel, P.O. Box, CH-4003 Basel, Switzerland.
authors: Jennifer
authors: J
authors: Keiser
authors: Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 02 BP 770, Abidjan 02, Côte d'Ivoire; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan 01, Côte d'Ivoire.
authors: Eliézer K
authors: EK
authors: N'Goran
authors: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, 80137 CREMOPAR, Italy.
authors: Davide
authors: D
authors: Ianniello
authors: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, 80137 CREMOPAR, Italy.
authors: Laura
authors: L
authors: Rinaldi
authors: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, 80137 CREMOPAR, Italy.
authors: Giuseppe
authors: G
authors: Cringoli
authors: Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland; University of Basel, P.O. Box, CH-4003 Basel, Switzerland.
authors: Jürg
authors: J
authors: Utzinger
mesh_terms: D000293:Adolescent; D000818:Animals; D001499:Bayes Theorem; D002648:Child; D002662:Child Health Services; D002675:Child, Preschool; D007560:Cote d'Ivoire / Q000453:epidemiology; D005243:Feces / Q000469:parasitology*; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012550:Schistosoma mansoni / Q000302:isolation & purification*; D012555:Schistosomiasis mansoni / Q000453:epidemiology* / Q000469:parasitology; D012574:Schools; D012680:Sensitivity and Specificity; D012987:Soil / Q000469:parasitology
chemical_list: D012987:Soil
keywords: Bayesian latent class analysis; Côte d’Ivoire; Diagnostic accuracy; Kato-Katz technique; Mini-FLOTAC; Schistosomiasis; Soil-transmitted helminthiasis