Development of a rapid serological assay for the diagnosis of strongyloidiasis using a novel diffraction-based biosensor technology

PLoS Negl Trop Dis. 2014 Aug 7;8(8):e3002. doi: 10.1371/journal.pntd.0003002. eCollection 2014 Aug.

Abstract

Background: Strongyloidiasis is a persistent human parasitic infection caused by the intestinal nematode, Strongyloides stercoralis. The parasite has a world-wide distribution, particularly in tropical and subtropical regions with poor sanitary conditions. Since individuals with strongyloidiasis are typically asymptomatic, the infection can persist for decades without detection. Problems arise when individuals with unrecognized S. stercoralis infection are immunosuppressed, which can lead to hyper-infection syndrome and disseminated disease with an associated high mortality if untreated. Therefore a rapid, sensitive and easy to use method of diagnosing Strongyloides infection may improve the clinical management of this disease.

Methodology/principal findings: An immunological assay for diagnosing strongyloidiasis was developed on a novel diffraction-based optical bionsensor technology. The test employs a 31-kDa recombinant antigen called NIE derived from Strongyloides stercoralis L3-stage larvae. Assay performance was tested using retrospectively collected sera from patients with parasitologically confirmed strongyloidiasis and control sera from healthy individuals or those with other parasitoses including schistosomiasis, trichinosis, echinococcosis or amebiasis who were seronegative using the NIE ELISA assay. If we consider the control group as the true negative group, the assay readily differentiated S. stercoralis-infected patients from controls detecting 96.3% of the positive cases, and with no cross reactivity observed in the control group These results were in excellent agreement (κ = 0.98) with results obtained by an NIE-based enzyme-linked immunosorbent assay (ELISA). A further 44 sera from patients with suspected S. stercoralis infection were analyzed and showed 91% agreement with the NIE ELISA.

Conclusions/significance: In summary, this test provides high sensitivity detection of serum IgG against the NIE Strongyloides antigen. The assay is easy to perform and provides results in less than 30 minutes, making this platform amenable to rapid near-patient screening with minimal technical expertise.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Helminth / blood*
  • Biosensing Techniques / methods*
  • Enzyme-Linked Immunosorbent Assay / methods
  • Female
  • Humans
  • Retrospective Studies
  • Serologic Tests
  • Strongyloides stercoralis / immunology*
  • Strongyloidiasis / diagnosis*

Substances

  • Antibodies, Helminth

Grant support

The National Reference Centre for Parasitology is supported by Public Health Agency of Canada/National Microbiology Laboratory grant HT070-010033. The study was supported by the Foundation of the Montreal General Hospital and the Research Institute of the McGill University Health Centre. PLC was supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre Infection Theme. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.