A new diagnostic strategy which uses a luminol-H2O2 system to detect helminth eggs in fecal sediments processed by the Helmintex method

PLoS Negl Trop Dis. 2020 Jul 30;14(7):e0008500. doi: 10.1371/journal.pntd.0008500. eCollection 2020 Jul.

Abstract

Schistosomiasis remains a serious public health problem in tropical regions, affecting more than 250 million people. Sensitive diagnostic methods represent key tools for disease elimination, in particular in areas with low endemicity. Advances in the use of luminol-based chemiluminescent techniques have enabled greater sensitivity and speed in obtaining results in different diagnostic settings. In this study, we developed a luminol-H2O2 chemiluminescence (CL) method to detect Schistosoma mansoni eggs in human fecal sediments processed by the Helmintex (HTX) method. After S. mansoni eggs were incubated with a solution of luminol-H2O2 the light emission was detected and measured by spectrophotometry at 431 nm for 5 min, using detection and counts of eggs by bright field optical microscopy as a reference. CL intensity was found to correlate with different sources and numbers of eggs. Furthermore, our results showed that the CL method can distinguish positive from negative samples with 100% sensitivity and 71% specificity. To our knowledge, this is the first study to report the use of CL for the diagnosis of helminths from fecal samples. The combination of the HTX method with CL represents an important advance in providing a reference method with the highest standards of sensitivity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Feces / parasitology*
  • Humans
  • Hydrogen Peroxide / chemistry*
  • Luminescent Measurements
  • Luminol / chemistry*
  • Mice
  • Ovum*
  • Schistosoma mansoni / isolation & purification*
  • Schistosomiasis mansoni / diagnosis*
  • Schistosomiasis mansoni / parasitology

Substances

  • Luminol
  • Hydrogen Peroxide

Grants and funding

Financial support (PVE 401904/2013-0) was provided by Conselho Nacional de Pesquisa e Desenvolvimento Tecnológico do Brasil (CNPq: www.cnpq.br), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES: www.capes.gov.br) “Auxílio-PE-Parasitologia 1427/2011/Edital 32”. C.Graeff-Teixeira is a recipient of a CNPq PQ 1D fellowship and grants (307005/2014-3). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.