Diagnostic sensitivity of direct wet mount microscopy for soil-transmitted helminth infections in Jimma Town, Ethiopia

  • Daniel Dana School of Medical Laboratory Science, Faculty of Health Science, Institute of Health, Jimma University, Jimma, Ethiopia
  • Johnny Vlaminck Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
  • Zeleke Mekonnen School of Medical Laboratory Science, Faculty of Health Science, Institute of Health, Jimma University, Jimma, Ethiopia
  • Mio Ayana School of Medical Laboratory Science, Faculty of Health Science, Institute of Health, Jimma University, Jimma, Ethiopia
  • Florian Vogt Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
  • Kristien Verdonck Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
  • Hannock Tweya The International Union against Tuberculosis and Lung Disease, Paris, France
  • Collins Timire The International Union against Tuberculosis and Lung Disease, Paris, France
  • Peter Geldhof Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
  • Bruno Levecke Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
Keywords: Soil-transmitted helminths, direct wet mount microscopy, Kato-Katz, McMaster, Mini-FLOTAC, composite reference standard

Abstract

Introduction: Soil-transmitted helminthiasis (STH) remains a major public health problem in school children in Ethiopia. Although direct wet mount microscopy (DWMM) is the means to diagnose parasitic diseases in health care facilities in Ethiopia, it remains unclear what its diagnostic performance is for STH.

Methodology: A cross-sectional study was performed in Jimma Town (Ethiopia) and included 600 children from 10 primary schools. The diagnostic sensitivity of DWMM was compared to a composite reference standard (CRS) consisting of Kato-Katz, McMaster and Mini-FLOTAC. We also explored the impact of intensity of infection (the highest faecal egg counts (FECs; expressed as eggs per gram of stool (EPG)) across the CRS) on the diagnostic sensitivity of DWMM.

Results: Based on the CRS, there were 210 Ascaris (35.0%), 312 Trichuris (52.0%) and 102 hookworm cases (17.0%). The median intensity of infections equalled 2,057 EPG for Ascaris, 200 EPG for Trichuris and 110 EPG for hookworms. The sensitivity of DWMM was 73.8% for Ascaris, but was around 17% for both Trichuris and hookworms. The sensitivity significantly increased with intensity of STH. For Ascaris, the odds for detecting an infection intensity of 1,000 EPG was 6.2 times higher than detecting an infection of 100 EPG. For Trichuris and hookworms, these odds ratios were 7.1 and 14.

Conclusions: The diagnostic sensitivity of DWMM is low for STH, but it is able to detect those subjects that are in the highest need of treatment, and hence contributes to the global goal to eliminate STH as a public health problem.

Published
2020-06-30
How to Cite
1.
Dana D, Vlaminck J, Mekonnen Z, Ayana M, Vogt F, Verdonck K, Tweya H, Timire C, Geldhof P, Levecke B (2020) Diagnostic sensitivity of direct wet mount microscopy for soil-transmitted helminth infections in Jimma Town, Ethiopia. J Infect Dev Ctries 14:66S-71S. doi: 10.3855/jidc.11733
Section
The Ethiopian SORT IT Course